Morphological and Agronomic Traits Variations for Mungbean Variety Selection and Improvement in Uganda

MORPHOLOGICAL AND AGRONOMIC TRAITS VARIATIONS FOR MUNGBEAN VARIETY SELECTION AND IMPROVEMENT IN UGANDA

A. WANIALE, N. WANYERA1 and H. TALWANA School of Agricultural and Environmental Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda 1National Semi-Arid Resources Research Institute, National Agricultural Research Organization, P. O. Box Soroti, Uganda Corresponding author: [email protected]

(Received 18 December, 2013; accepted 5 May, 2014)

ABSTRACT

Mungbean (Vigna radiata L. Wilczek), is a pulse species that is widely cultivated in sub-tropical and tropical regions of the world. Unfortunately, the yield of mungbean in Uganda is very low mainly due to inherent genotype failures and losses due to pests and diseases. To achieve a gain in yield through breeding requires collection, characterisation, and evaluation of germplasm, as the first step in identifying genotypes with the desired characteristics. The objective of this study was to describe the nature and extent of genotypic variation among mungbean collections for a range of traits of potential agronomic and adaptive interests in Uganda. A total of 35 mungbean accessions acquired mainly from the World Vegetable Centre (AVRDC) in Taiwan, two local ricebean (Vigna umbellata (Thunb.) Ohwi and Ohashi) and one local blackgram genotype (Vigna mungo) were evaluated for several diverse traits for two cropping seasons at two different locations in Uganda. Genotype by environment interaction (GEI) was significant (P < 0.001) for all the traits, indicating inconsistent performance by some genotypes across two locations and two seasons. However, AMMI bi-plot identified stable genotypes for grain yield, while GGE bi-plot identified the best genotypes in a hypothetical environment. The magnitudes of estimated broad sense heritability (H) for the traits used were generally high. However, single link dendogram and Principal Component Analysis (PCA) revealed narrow diversity in the mungbean collection. The positive relationship between seed size and yield in this sub-set of mungbean germplasm can be used in a breeding programme for a potential gain in selecting large seeded and high yielding genotypes.

Key Words: Vigna mungo, Vigna radiata, Vigna umbellata

RÉSUMÉ

Le haricot mungo (Vigna radiata L. Wilczek), est une espèce de plante qui est largement cultivée en régions tropicales et subtropicales. Le rendement actuel du haricot mungo en Ouganda est comparativement bas par suite d’échecs liés au génotype et pertes dues aux maladies et pestes. Afin de réaliser un gain de rendement à travers l’amélioration, il s’avère nécessaire de faire la collection, la caractérisation, et l’évaluation du germplasme, comme première étape dans l’identification des génotypes avec des caractéristiques désirées. La variation parmi 38 accessions de haricot mungo obtenues du World Végétale Centre (AVRDC), une variété locale de haricot riz (Vigna umbellata (Thunb.) Ohwi et d’ Ohashi) et un génotype de blackgram (Vigna mungo) local, était évaluée pour plusieurs traits directs pendant deux saisons culturales dans des lieux différents en Ouganda. Une variation substantielle était observée dans différent traits de potentiel agronomique et performance adaptive. L’interaction génotype par environnement (GEI) était significatif (P < 0.001) pour tous les traits, indiquant une performance inconsistante de quelques génotypes à travers deux milieux et deux saisons. Par ailleurs, un AMMI bi-plot a identifié des génotypes stables en termes de rendement en grain, alors que le GGE bi-plot a identifié les meilleurs génotypes dans un environnement hypothétique. Les niveaux de l’héritabilité estimée (H) pour les traits utilisees étaient généralement élevés. Par ailleurs, le lien simple du dendogramme et l’analyse par composantes Principales 124 A. WANIALE et al. (PCA) ont révélé une petite diversité dans la collection du haricot mungo. Une corrélation positive entre la taille du grain et le rendement dans ce sous groupe du germoplasme du haricot mungo peut être utilisée dans le programme d’amélioration pour un gain potentiel dans la sélection des génotypes à grains larges et rendement élevés.

Mots Clés: Vigna mungo, Vigna radiata, Vigna umbellata

INTRODUCTION million metric tons harvested from about 5.5 million hectares (Poehlman, 1991; Weinberger, Mungbean (Vigna radiata L. Wilczek) is a pulse 2003), of which 90% is in South Asia, especially species of the pan-tropical genus Vigna in Bangladesh, Burma, India, Indonesia, Pakistan, (Saravanakumar et al., 2004) that is native to Asia Philippines, Sri Lanka and Thailand but widely cultivated in Africa, Asia and Latin (Shanmugasundaram, 2001). The holistic America (Tomooka et al., 1992). Its short growth mungbean improvement program of the World duration allows adaptation to many cropping Vegetable Centre (AVRDC) in the region is largely systems and rotations, hence, diversifying credited for this improvement cropping systems (Shanmugasundaram et al., (Shanmugasundaram et al., 2009). 2009). Meanwhile, its remarkable quality of fixing In sub-Saharan Africa, mungbean production atmospheric nitrogen enriches soils (Sharma et still depends on the small-seeded traditional al., 1996) and its low soil water and fertility varieties, which reach maturity in 90 -110 days. requirements (Sangakkara et al., 2001) increases The varieties are indeterminate in growth and cropping systems productivity and resilience have to be harvested multiple times; yet they are (Ahmad et al., 2001; Keatinge et al., 2011). susceptible to diseases and insect pests, and pod Mungbean can provide significant amounts shattering (Shanmugasundaram, 1988). Worse of protein (240 g kg-1), carbohydrate (630 g kg-1) still, these varieties are low yielding, producing and a range of micronutrients in diets (Anwar et only about 200 - 500 kg ha-1 (Agugo and Chukwu, al., 2007). Mungbean protein and carbohydrates 2010). Fortunately, they are fairly adapted to the are easily digested and create less flatulence than local environmental conditions (Mbowe, et al., those derived from other legumes (Fleming, 1981). 1987). The desired characteristics and The mungbean lysine content of 504 mg g-1 performance of the imagined ideal variety needed (Saini et al., 2010) makes it a good supplement for to transform mungbean from a marginal to a major most cereal based diets which lack this essential crop in sub-Saharan Africa include synchronous amino acid (Baskaran, et al., 2009). In addition, maturity, larger seeds, higher seed quality and mungbean is lower in phytic acid, which is yield, and resistant to diseases and insect pests. commonly high in cereal and other legume crops, The objective of this study was to describe the and has a negative impact on iron and zinc nature and extent of genotypic variation among bioavailability in plant-based diets (Kataria et al., mungbean collections for a range of traits of 1989). Thus, mungbean as a major protein potential agronomic and adaptive interests in supplement in cereal-based diets (Thirumaran and Uganda. Seralathan, 1988). It is eaten as boiled beans (Abbas, et al., 2010), soup or mungbean pancake MATERIALS AND METHODS (Gwag, et al., 2006). Owing to its palatable taste and nutritional quality, mungbean has been used A total of 35 mungbean accessions (Table 1) as an iron-rich whole food source for baby food were evaluated in contrasting environments to (Sosulski et al., 1976; Del Rosario et al., 1987). document the expression of 14 quantitative and World production statistics for mungbean are 28 qualitative mungbean plant traits during plant difficult to obtain; for example, FAOSTAT growth (Bisht et al., 2005). The accessions includes mungbean together with species from consisted of 25 lines introduced from AVRDC in the genus Phaseolus under dry beans. Annual 2010; 7 lines earlier introduced from AVRDC by world mungbean production is estimated at 3 the Small grain Legumes Research Programme of Morphological and agronomic traits of mungbean varieties 125 TABLE 1. List of mungbean and other genotypes used in the the National Semi-Arid Resources Research study and their origins Institute (NaSARRI) Uganda and 3 local varieties ‘ collected from farmers in eastern Uganda. No. Accession number Country of origin Additionally, 2 local ricebean lines collected from farmers in north western (West Nile region) Mungbean lines newly (2010) acquired from AVRDC Uganda and 1 blackgram line from AVRDC were 1. V01128 A-G India included in the evaluation. 2. V01128 B-G India Four contrasting experimental environments 3. V02366 A-G India were obtained by growing the accessions in 2 4. V02500 A-G India different growing seasons: September - December 5. V02551 A-G India 2011 and April - August 2012; in 2 different sites: 6. V02551 B-G India Makerere University Agricultural Research 7. V02757 A-G India Institute Kabanyolo (MUARIK) and National 8. V02817 B-G Nigeria Semi-Arid Resources Research Institute 9. V04679 B-BR India 10. V04717 B-G India (NaSARRI) Serere, with the purpose of eliciting 11. V05000 B-G India differential responses among the mungbean 12. V06094 A-Y Philippines accessions to climatic conditions experienced 13. V06321 B-G Taiwan during the two cropping seasons at the two sites. 14. V06322 A-G Taiwan MUARIK (0°28'N, 32°37'E; altitude 1285 m 15. V06323 A-G Taiwan above sea level) is located in central Uganda, a 16. V06327 A-G Taiwan region characterised by high rainfall (about 1300 17. V06327 A-BR Taiwan mm) distributed in a bimodal pattern with an 18. V06332 A-BR Taiwan annual mean daily temperature of 24o C 19. V06332 A-G Taiwan 20. V06342 A-G Taiwan (Wortmann and Eledu, 1999). The soils are deep, 21. V06347 B-G Taiwan highly weathered and classified as Latosols and 22. TV01251 A-G Indonesia Ferrallitic, with a pH of 5.0 - 6.0. 23. TV03718 A-G India On the other hand, NaSARRI (0°32'N, 35°27'E; 24. TV03719 A-G India altitude 1140 m) is located in northeastern 25. TV03720 A-G India Uganda, a zone that has an average annual rainfall of 1100 mm also divided into two peaks. The Mungbean lines acquired earlier (2008) from AVRDC annual mean daily temperature is about 26 o C. The soils are sandy loams of medium to low 26. VC6153 (B-20) 27. VC6173 (B-10) fertility and soil pH 5.2 to 6.0 (Tumwegamire et 28. VC6148 (50-12) al., 2011). 29. VC6137 (B-14) Mungbean seeds were hand planted in 1.5 m2 30. VC6372 (45-60) plots at a spacing of 10 cm within rows and 50 cm 31. KPSI between rows. The plots were arranged in 8 32. Mauritius blocks (5 plots within each block) within an alpha 33. Black gram lattice design and replicated 3 times. Borders comprising of the local farmers’ line were planted Mung and rice bean lines collected from farmers in Uganda around the perimeter of each block. 34. Sor I (Mungbean) 35. Sor II (Mungbean) Data collection. Twenty eight distinct qualitative 36. Pallisa (Mungbean) and 14 quantitative descriptors of phenology, 37. Sor III Red (Ricebean) pod and seed traits and seed yield based on the 38. Sor III Green (Ricebean) Bisht et al. (2005) descriptor list (Table 2) were assessed. Plots were monitored regularly and data AVRDC = World Vegetable Centre on dates for flowering (the appearance of the first 126 A. WANIALE et al. 6. Climbing 5. Prostrate 5– others 5. Densely pubescent 5. Others 5. Others 5. Very deep 5. Others 4. Semi-prostrate 4– dark purple 4. Moderately pubescent 4. Rhombic 4. Pendent 4. Deep 4. Green-purplish yellow 4. Highly pubescent 4. Densely pubescent 4. Others 4. Densely pubescent ellowish green Y 3. Petiolate 3. Spreading 3– light purple 3. Sparsely pubescent 3. Abundant 3. Ovate 3. Horizontal-pendent 3. Pronounced 3. Throughout canopy 3. Intermediate 3. 3. Moderately pubescent 3. Moderately pubescent 3. Synchronous 3. Others 3. Greenish purple 3. Others 3. Others 3. Curved (sickle shaped) 3. Large 3. Moderately pubescent 3. Large 2. Sub-sessile 2. Hypogeal Semi-erect pubescent 2– dark green 2. Very sparsely 2. Intermediate 2. Broadly ovate 2. Horizontal 2. Slight 2. In upper canopy 2. Shallow 2. Greenish yellow 2. Sparsely pubescent 2. Pubescent 2. Intermediate 2. Blunt 2. Purplish green 2. Lanceolate 2. Lanceolate 2. Slightly curved 2. Medium pubescent 2. Sparsely 2. Intermediate ellow Y 1. Sessile 1. Epigeal 1. Erect 2 1– light green 1. Glabrous 1. Sparse 1. Lanceolate 1. Erect 1. Absent 1. Mostly above 1. Unlobbed 1. Glabrous 1. 1. Glabrous 1. Asynchronous 1. Pointed canopy 1. Green 1. Ovate 1. Linear 1. Straight 1. Small 1. Glabrous 1. Small Qualitative descriptors and their scores erminal leaflet lobe shape Attachment of primary leaves Seed germination habit (at two leaf stage) Growth habit (recorded at first pod maturity) Stem colour Leaf pubescence Leafiness (at 50% flowering) (at first pod maturity) T Pod attachment to peduncle Constriction of pod between Raceme position (at first pod Lobbing of terminal leaflet Stem pubescence Corolla colour Petiole pubescence Flowering period Pod beak shape seeds maturity) Calyx colour Stipule shape Bracteole shape Pod curvature Stipule size Pod pubescence Bracteole size ABLE 2. List of mungbean genotypes descriptors studied/measured in Uganda 1. 2. T Serial number 1. 3. 4. 6. 5. 9. 19. 23. 13. 8. 12. 15. 7. 18. 22. 14. 1 17. 21. 10. 20. 16. Morphological and agronomic traits of mungbean varieties 127 1. Green brown 7. Others 7. Mottled grey 8. Mottled brown 9. Mottled cream 10. Light cream 1 12. Chocolate 13. Black 6. Drum shaped 6. Grey 5. Kidney shaped 5. Dark brown 4. Cubical to oblong 4. Others 4. Heavy 4. Intermediate brown 3. Narrowly ellipsoid 3. Others 3. Convex 3. Intermediate 3. Light brown , plants were stretched out to the tip. . . . 2. Ovoid 2. Round 2. Plain 2. Slight 2. Present 2. Cream 1. Globose 1. Semi flat 1. Concave 1. Absent 1. Absent 1. White . (2005) et al Qualitative descriptors and their scores erminal leaflet length (cm) – Length from base to the tip of expanded terminal leaflet. erminal leaflet width (cm) – Length of the widest part an expanded terminal leaflet. Seed shape Pod length (cm)– Length from point of pod attachment to the tip taken after harvest. Number of seeds per pod – Counted after harvest. 100-seed weight (g) – Dried seeds were counted and weighed using a digital electric weighing scale. Yield per plant (g) – Weight of dried seed from 3-5 well bordered plants was taken using a digital electric weighing scale and averaged to get yield plant. Plant height (cm) – Measured with a meter rule at harvest maturity Pod cross section Number of pods per cluster – Counted at harvest maturity Days to first flowering – Number of days from planting appearance flower. Days to maturity – Number of days from planting 80% dry pods. T T Petiole length (cm) – Length from point of attachment to trifoliate leaflets. Peduncle length (cm) – Length from point of attachment to cluster flowers. Number of primary branches – counted at 80% maturity Hilum shape Mottling on seed surface Number of pods per plant – Counted at harvest maturity Lusture on seed surface Seed colour ABLE 2. Contd. 1. 1 25. 12. 13. 14. Source: Bisht 8. T Serial number 24. 10. 2. 3. Quantitative descriptors 1. 4. 6. 7. 5. 29. 28. 9. 27. 26. 128 A. WANIALE et al. flowers on 50% of plants), and the physiological means, respectively. All analyses were done using maturity (85% of pods ripened) recorded. Data the 14th edition Genstat Statistical computer on phenology descriptors including terminal software. leaflet length (cm), terminal leaflet width (cm), petiole length (cm), plant height (cm), peduncle RESULTS AND DISCUSSION length (cm), number of primary branches; pod traits including number of pods per plant, number Ricebean genotypes had exceedingly high of pods per cluster, pod length (cm); and seed variable means, especially yield, compared to the traits including number of seeds per pod, 100 - mungbean genotypes in the sub-set evaluated seed weight (g) and yield per plant (cm), were (Table 3) and, thus, were excluded from further collected from a random sample of five well- analysis. The mungbean genotypes were bordered plants of each accession. compared as groups according to where/when Data on 28 qualitative descriptors was used collected (Table 1), and there were significant to draw a single link dendrogram, while data on differences in all quantitative traits across the the 14 quantitative descriptors were subjected to two locations and the two seasons within and analysis of variance (ANOVA) using Genstat (4th between these mungbean groups (Table 4). This Edition). Individual replication data were used suggests presence of a substantial amount of for Additive Main Effects and Multiplicative variability among the genotypes studied. Interactions (AMMI) analysis. Broad Sense However, since the grouping was based on Heritability (H) was estimated using variance geographic origin/distribution of genotypes, the components. An AMMI plot of the interactive observed genetic diversity may be misleading principal component analysis (IPCA) scores and (Das et al., (2010). genotype-environment means, as well as a The coefficient of variation was highest for genotype plus genotype-by-environment grain yield per plant across the four environments variation (GGE) scatter bi-plot were drawn. but error mean square for grain yield per plant Principal component scores and correlations were was fairly low (Table 4). This indicates the highly calculated using environmental means and overall variable but low yield of the evaluated genotypes.

TABLE 3. Four environment means (± se), range and standard deviations of farmer lines, AVRDC lines, NaSARRI mungbean collections, Black Gram and Rice Bean for 14 Quantitative Traits

Quantitative trait Mungbean Mungbean lines Mungbean lines Black gram Rice bean lines collected newly (2010) acquired earlier from farmer acquired from (2008) from AVRDC AVRDC

Days to first flowering 48.3 ± 2.6 39.1 ± 1.5 38.2 ± 1.4 44.0 ± 1.2 53.2 ± 2.1 Days to 80 maturity 91.9 ± 7.0 71.1 ± 2.6 70.7 ± 2.0 92.9 ± 2.4 104.1 ± 1.4 Terminal leaflet length (cm) 9.7 ± 0.7 8.8 ± 0.9 8.7 ± 1.1 10.2 ± 1.1 10.6 ± 1.1 Terminal leaflet width (cm) 8.6 ± 0.8 6.9 ± 0.9 7.2 ± 1.1 6.1 ± 1.0 6.7 ± 0.8 Petiole length (cm) 13.1 ± 1.2 10.2 ± 1.4 9.8 ± 1.2 13.0 ± 1.9 17.1 ± 3.3 Peduncle length (cm) 4.8 ± 1.4 5.4 ± 1.4 6.1 ± 1.8 3.0 ± 1.0 10.5 ± 1.2 Number of primary branches 2.9 ± 0.6 1.8 ± 0.4 1.5 ± 0.3 2.9 ± 0.4 4.3 ± 0.8 Pods per plant 26.3 ± 7.5 15.0 ± 3.5 13.8 ± 3.0 44.6 ± 9.5 75.5 ± 14.9 Pods per cluster 3.6 ± 0.7 3.7 ± 0.5 3.6 ± 0.5 3.6 ± 0.3 4.9 ± 0.5 Plant height (cm) 41.8 ± 6.5 26.4 ± 4.5 28.5 ± 3.9 28.8 ± 9.1 101.4 ± 13.1 Pod length (cm) 7.4 ± 0.4 7.0 ± 0.5 8.4 ± 0.6 4.9 ± 0.3 9.1 ± 0.7 Seeds per pod 11.4 ± 1.1 10.0 ± 1.1 9.4 ± 1.0 6.7 ± 0.7 6.5 ± 0.8 100 seed weight (g) 3.5 ± 0.4 3.8 ± 0.4 5.3 ± 0.4 3.9 ± 0.4 6.7 ± 0.4 Grain yield per plant (g) 6.6 ± 2.1 3.9 ± 1.2 4.9 ± 1.5 8.6 ± 1.4 22.1 ± 6.0

VRDC = World Vegetable Centre Morphological and agronomic traits of mungbean varieties 129

TABLE 4. Relative magnitudes of mungbean accessions (G) and accessions x environment (G x E) effects and broad sense heritability for selected traits of local and imported Mungbean lines when grown in 4 contrasting environments in Uganda

Source Genotype GXE Error’ BSCGD %CV

Degrees of freedom 35 105 256 Days to first flowering 34.4*** 2.9*** 0.9 0.87 2 Days to 80 maturity 189.1*** 12.3*** 4.1 0.90 3 Terminal leaflet length (cm) 1.2*** 0.5*** 0.3 0.39 6 Terminal leaflet width (cm) 2.5*** 0.5*** 0.3 0.65 7 Petiole length (cm) 5.7*** 1.7*** 0.5 0.60 7 Peduncle length (cm) 2.1ns 2.0*** 0.7 0.03 15 Number of primary branches 0.9*** 0.2*** 0.1 0.72 13 Pods per plant 158.9*** 14.3*** 5.7 0.85 14 Pods per cluster 0.1ns 0.2*** 0.1 0.00 8 Plant height (cm) 116.8*** 15.8*** 7.0 0.77 9 Pod length (cm) 4.3*** 0.2*** 0.1 0.91 4 Seeds per pod 2.9*** 0.8*** 0.4 0.59 6 100 seed weight (g) 5.8*** 0.2*** 0.1 0.95 6 Grain yield per plant (cm) 7.4*** 2.4*** 0.7 0.57 19

BSCGD – Broad Sense Coefficient of Genetic Determination calculated on genotype means basis across environments. Trait level of significant difference: *: P<0.05; **: P<0.01; ***: P<0.001; ns = not significant

The low yield obtained can be attributed to high the Generalised Linear ANOVA and AMMI incidence and severity of Anthracnose (data not ANOVA. A symmetric scaling of genotype plus reported) among the genotypes. Broad Sense genotype-by-environment variation (GGE) Coefficient of Genetic Determination (BSCGD) scatter plot showed that the four environments estimating Broad Sense Heritability (H), was fairly were in different sectors of the plot (Fig. 2). This high for the majority of the measured traits (Table is a case of crossover G - E interaction, implying 4). This suggests that genetic variance was far that the target environment may be divided into more important than variability due to different sub-environments (Yan et al., 2007). environment as asserted by Bernardo, 2002, Subsequently, NaSARRI and MUARIK 2011B further implying that the mungbean traits studied were grouped together as mega environments; can be selected with fewer challenges. while NaSARRI and MUARIK 2012A were unique From AMMI ANOVA, environments were environments, when the criteria of Yan and Rajcan significantly different for all the measured traits (2002) was used. The winning genotypes in the (Table 5). Additionally, both Generalised Linear experimental environments as illustrated in Figure and AMMI ANOVA showed significant (P<0.001) 2 are the local genotype SOR II (35) in MUARIK genotype-environment interactions (GEI) for all 2012A environment, Blackgram (33) and MUARIK measured traits. This implies that the assembled 2011B and NaSARRI 2011B (32) in environments lines did not perform consistently across the NaSARRI 2012A. environments and, therefore, it would be beneficial There were positive and significant linear to evaluate the genotypes in more than one correlations between yield and early maturity, as environment (Yan and Kang, 2003). An AMMI well as leaf size and petiole length (Table 6). biplot using grain yield per plant showed Whereas the common concept is that there is a genotypes 13 (V06321 B-G) and 18 (V06332 A- trade-off of reduced yield in selecting early BR) as the most stable; while genotype 34 (Sor I) maturity (Gambin and Borrás, 2010), there was an as the most unstable across the environments increase in yield in early maturing mungbean lines, (Fig. 1). The unstable genotypes 1 (V01128 A-G), possibly due to a large photosynthetic area/leaf 23 (TV03718 A-G), 34 (Sor 1) and 36 (Pallisa) were size (Borrel et al., 2000). This is further affirmed responsible for the significant GEI observed in by the relation between yield traits, traits related 130 A. WANIALE et al. 2.8 0.9 0.8 280 Errors 13.1 1.8 2.2 17.4 0.2 0.3 1.1 0.2 23.9 0.2 2 1.1ns Res 7.5ns 2.1ns 0.6ns 20.1ns 0.2ns 0.4* 1.1ns 0.2ns 20.7ns 0.3ns 1.8ns 1.3* 13.0ns 6.4*** 1.7*** 4.9*** 1.0ns 1.0ns 31.3** 0.5** 37.1* 4.3*** 85.0*** 17.1*** 37 35 33 12.9*** IPCA IPCA 14.8*** 366.6*** 1.5*** 2.4*** 8.7*** 105 6.4*** GXE 0.5*** 0.7*** 50.1*** 88.8*** 7.2*** 2.3*** 3.3*** 2.4*** 0.5*** 0.7*** 0.4*** 0.7*** 1.1*** 0.6*** 1.8*** 33.1* 19.5*** 8.5*** 5.2*** 9.0*** 4.1*** 8.1*** 1.6*** 2.4*** 4.7ns 23.2*** R/Envt 1.2*** 0.5*** 1.0*** 0.4*** 62.0*** 42.8*** 74.0*** 0.6* 209.7*** 1 2.4* 0.5** 0.6* 7018*** 212*** 449*** 202*** 1367*** 1361*** Envt 40*** 3 8 1434*** 20*** 7644*** 410*** 48*** 27*** 28*** 102.2*** 6.6*** Gen 35 0.4ns 17.4*** 13.0*** 313.1*** 567.8*** 7.3*** 7.3*** 17.5*** 17.5*** 6.3*** 3.5*** 60.1*** 34.9*** Trts 1.9*** 2.8*** 0.9*** 178.9*** 479.5*** 289.1*** 375.4*** 5.2*** 19.3*** 22.3*** 4.3*** 4.9*** 8.8*** otal 15.3 13 1 3.3 7.2 2.8 21.8 431 143 13.4 T 0.8 0.5 71.8 1 1.8 7.9 1.6 2.4 for 14 mungbean quantitative traits from 4 environments in Uganda A ANOV AMMI ABLE 5. erminal leaflet width (cm) erminal leaflet length (cm) Days to 80 maturity T Petiole length (cm) Days to first flowering Degrees of freedom T Peduncle length (cm) Source T Number of primary branches Pods per cluster Pods per plant Plant height (cm) 100 seed weight (g) Grain yield per plant (cm) Pod length (cm) Seeds per pod Trait level of significant difference; * at P<0.05, ** P<0.01, *** P<0.001 and ns = none Morphological and agronomic traits of mungbean varieties 131 IPCA scores

Genotype and environment means Figure 1. An AMMI biplot using mean yield per plant (Seasons: 2011B = September – December 2011; 2012 = April – August 2012) in Uganda.

PC1 - 68.09% PC2 - 20.63%

Figure 2. A symmetric scaling GGE scatter plot showing genotype scores, winning genotypes and mega environments seasons: 2011B = September – December 2011, 2012A = April – August 2012. 132 A. WANIALE et al. 0.48** 100SW - , Plt Ht = Plant erminal Leaflet T = 1 TLL , -0.1 SPP -0.22 - 1 0.31 PodL 0.84*** 0.1 - 0.51** Plt Ht -0.14 0.06 - -0.41* PPClu 0.16 0.31 -0.40* - -0.19 - 0.58*** PPPlt -0.35* -0.35* -0.26 -0.52** 0.49** - 0.75*** 0.44** Prim Br -0.45** -0.39* 0.60*** -0.58*** - -0.65*** -0.14 PedL 0.43** 0.58*** -0.07 - 0.74*** -0.34* 0.67*** 0.63*** PetL -0.13 -0.10 0.15 0.18 0.22 = Peduncle Length, Prim Br Number of Primary Branches, PPPlt Pods Per Plant, PPClu Cluster W 0.28 - 0.14 0.07 0.52** TL 0.46** 0.36* ference from zero: * at P<0.05, ** P<0.01, *** P<0.001. DTFF = Days to First flowering, DTM 80% Maturity = Petiole Length, PedL -0.36* 0.68*** - 0.03 0.32 TLL -0.05 idth, PetL ficients between measured traits for mungbean genotypes evaluated in Uganda -0.54*** - DTM 0.76*** 0.66*** 0.69*** 0.79*** 0.09 ficient significant dif erminal Leaflet W T 0.81*** 0.84*** 0.79*** 0.64*** 0.84*** 0.82*** 0.60*** -0.39* 0.45** 0.44** 0.92*** 0.58*** 0.72*** 0.68*** 0.85*** 0.61*** 0.57*** 0.69*** 0.66*** -0.15 -0.19 -0.29 -0.23 -0.15 -0.15 -0.02 -0.09 -0.27 -0.20 DTFF 0.79** -0.140.36* -0.20 -0.01 W = TL W ABLE 6. Correlation coef PetL Prim Br Level of correlation coef TL PedL DTM TLL PPPlt Length, YPPlt Height, PodL = Pod Length, SPP Seeds Per Pod, 100 SW Seed Weight, YPPlt Yield Plant PPClu 100SW T Plt Ht PodL SPP Morphological and agronomic traits of mungbean varieties 133

TABLE 7. First 4 of 14 Principal Components using 14 mungbean traits averaged across four environments in Uganda

1 2 3 4

Days to first flowering 0.26 0.14 0.28 -0.42 Days to 80 maturity 0.66 0.01 0.54 -0.10 Terminal leaflet length (cm) 0.04 0.01 0.00 0.10 Terminal leaflet width (cm) 0.03 0.12 0.06 0.13 Petiole length (cm) 0.10 0.06 0.02 0.04 Peduncle length (cm) -0.04 0.09 -0.04 0.12 Number of primary branches 0.04 -0.01 0.01 -0.08 Pods per plant 0.55 -0.64 -0.41 0.18 Pods per cluster 0.00 -0.01 -0.02 -0.04 Plant height (cm) 0.42 0.71 -0.52 0.13 Pod length (cm) -0.03 0.14 0.22 0.33 Seeds per pod 0.00 0.12 0.09 -0.28 100 seed weight (g) -0.03 0.06 0.28 0.55 Grain yield per plant (cm) 0.09 0.01 0.22 0.47

Latent roots 105.46 18.44 4.32 2.96 Variation (%) 79.28 13.86 3.25 2.22 Trace 133

Figure 3. A single link dendrogram using qualitative descriptors of mungbean evaluated in Uganda. 134 A. WANIALE et al. to plant vigour and earliness (Table 6). Seed size, (James et al., 1999). The GGE was significant for which is a critical mungbean trait, was positively stability and performance of the mungbean sub- correlated with seed yield, implying that large set evaluated, thus necessitating further multi- seeded and high yielding lines can easily be location and multi-season trials to improve the selected together (Mishra and Singh, 2012). breeding and selection efficiency. Principal Component Analysis (PCA) using genotype means of 14 quantitative descriptors ACKNOWLEDGMENT showed that the first two Principal Components jointly accounted for 93% of the observed This study was funded by the Regional variation (Table 7). Days to maturity, pods per Universities Forum for Capacity Building in plant and plant height were the most important Agriculture RUFORUM Grant No. traits. Since a very large amount of variability RU2010GRG16. The World Vegetable Center was explained by the first two Principal (AVRDC) provided the mungbean accessions Components, it can be inferred that there is narrow used in this study. diversity in the evaluated genotypes, contrary to the inferance from analysis of variance (Table REFERENCES 4). A dendrogram constructed using data of 28 Abbas, G., Asghar, M. J. and Shah, T. M. 2010. qualitative descriptors showed 90-100% similarity Genetic diversity in mungbean (Vigna radiata among the genotypes (Fig. 3). This implies that, (L.) Wilczek) germplasm. Pakistan Journal either the morphological markers were not of Botany 42:3485-3495. polymorphic enough or there is less genetic Agugo B.A.C. and Chukwu, G.O. 2010. Predicting distance among the mungbean lines. 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