Euphytica (2018) 214:192 https://doi.org/10.1007/s10681-018-2271-7 (0123456789().,-volV)(0123456789().,-volV) Combining ability and heritability of soybean resistance to groundnut leaf miner A. P. Ibanda . G. M. Malinga . G. A. Tanzito . D. Ocan . A. Badji . N. Mwila . U. Msiska . T. L. Odong . J. Karungi . P. Tukamuhabwa . P. R. Rubaihayo Received: 18 March 2018 / Accepted: 25 September 2018 Ó Springer Nature B.V. 2018 Abstract Groundnut leaf miner (GLM) (Aproaer- December 2016 rainy season. Highly significant ema modicella) (Deventer) is one of the most differences were observed among parental genotypes destructive pests of soybean and groundnuts. In this and F2 populations for GLM incidence, severity, and study, the mode of inheritance, general combining grain yield. The estimates of GCA effects were ability (GCA), specific combining ability (SCA) significant for GLM incidence and severity scores effects, maternal effects of resistance to GLM and but not for the number of larvae per plant and grain grain yield ha-1 were determined. Thirteen soybean yield ha-1. SCA effects were non-significant for all parental genotypes and 81 F2 populations were the studied traits, suggesting that GCA effects were the evaluated for resistance to GLM in a 5 9 19 alpha major component responsible for soybean resistance lattice diallel design with two replications under to GLM with additive gene effects being more natural GLM infestation in northern (Arua) and important for these traits. Baker’s ratio ranged from eastern (Iki-iki) Uganda during September to 0.44-1.0 for most of resistant traits except number of larvae per plant and grain yield ha-1. The results indicated also that cultivars Maksoy1 N, PI615437, A. P. Ibanda (&) Á G. A. Tanzito Á D. Ocan Á PI578457A and NIIGC4.1-2 were good combiners A. Badji Á N. Mwila Á U. Msiska Á T. L. Odong Á against GLM incidence and severity. Parent PI615437 J. Karungi Á P. Tukamuhabwa Á P. R. Rubaihayo was a good combiner for grain yield and Mak- College of Agricultural and Environmental Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda soy1 N 9 PI615437 was a superior cross for grain e-mail: [email protected] yield and against GLM incidence. There were no maternal effects for the inheritance of resistance to G. M. Malinga GLM. The study provides a basis for understanding Department of Biology, Gulu University, P. O. Box 166, Gulu, Uganda patterns of inheritance of soybean resistance to groundnut leaf miner for an efficient breeding G. M. Malinga program. Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland Keywords Additive gene effects Á Diallel analysis Á Incidence Á Severity Á Aproaerema modicella G. A. Tanzito Department of Crop Sciences and Production, Institut Facultaire Des Sciences Agronomiques de Yangambi, P.O. Box 1232, Kisangani, Democratic Republic of the Congo 123 192 Page 2 of 15 Euphytica (2018) 214:192 Introduction can develop a high degree of resistance to a broad range of insecticides over a relatively short time (Mou Soybean, Glycine max (L.) Merr. is one of world’s 2008). The resource-poor soybean producers in Sub- leading oil crop, providing the cheapest food and Saharan Africa have limited funds for buying pesti- source of proteins for the poor rural communities cides (Munyuli et al. 2003). Given the negative aspects (Bilyeu et al. 2010). Nutritionally, soybean grains of reliance on pesticides, host-plant resistant cultivars contain about 40% protein, 20% oil, with an optimal is a more sustainable integrated management approach supply of essential amino acids and nutrients, and a to leaf miner control (Hill et al. 2009). high-calorie value (Singh et al. 2008). In Uganda, Makerere University through the Centre for Soy- soybean is increasingly becoming an important food bean Improvement and Development released twelve and cash crop (Tukamuhabwa et al. 2011) and the land moderately resistant soybean genotypes (Namara et al. area under soybean production increased from 2015). However, knowledge regarding genetic control 144,000 to 155,000 hectares between 2004 and 2009, and heritability of resistance to GLM and its relation- with annual production increasing from 158,000 to ship to other plant traits is needed to be able to develop 181,000 tonnes, respectively (Tukamuhabwa and appropriate procedures in the breeding for resistance. Oloka 2016). Northern and Eastern regions account Previous genetic studies on other soybean defoliating for most of the production in the country with 66.6% insect pests suggested that inheritance of resistance and 24.6%, respectively (UBOS 2010). Despite the was quantitatively inherited (Rector et al. 2000) and increasing trend of soybean production in Uganda over either controlled by a single incompletely dominant the past 10 years, the current yields estimated at about (Ojo and Ariyo 1999) or multiple genes (Mebrahtu 1200 kg ha-1 are still below the potential of et al. 1990). The incorporation of the genes for GLM 2000 kg ha-1 reported in other major producing resistance into cultivars with desirable agronomic countries in Africa (FAO 2011). According to Tuka- traits and high yielding is a goal actively pursued in muhabwa (2001), the low yields are due to a number of soybean breeding programmes in Uganda. It is constraints including insect pests, diseases, low soil important to understand the nature of the gene action fertility, drought and lack of inputs among others. to help the breeders to select the suitable parents for The Groundnut leaf miner (GLM) Aproaerema the crossing programme (Maphosa et al. 2012). The modicella (Deventer) (Lepidoptera: Gelechiidae) is objective of this study was to determine the mode of one of the most serious invasive oligophagous pest inheritance and to identify parents with high combin- affecting soybean (Glycine maxima L.) and groundnut ing abilities for soybean GLM resistance. (Arachis hypogaea L.) production in Indo-Asia and Africa leading to huge yield loss of up to 100% in the tropics (Cugala et al. 2010, Praveena et al. 2011, Materials and methods Buthelezi et al. 2013). In Africa, first report of GLM was on groundnut during 1998 (Page et al. 2000). In Experimental site and germplasm Uganda, the pest severely affects soybean (Namara et al. 2015) and groundnut (Page et al. 2000; Epieru The study was carried at locations in soybean growing 2004; Okello et al. 2010) particularly during the areas of northern and eastern Uganda. The first second rainy season (August-December), in Eastern experimental location was at the District Agricultural and Northern regions causing up to 54% yield loss in Training and Information Centre in Iki-iki sub-county, soybean (Namara et al. 2015). GLM damage is Budaka district (1°060N, 34°000E) located at 1156 m characterized by the leaf-mining of larvae between asl with a mean annual rainfall of 1200 mm and the epidermis and longitudinal folding of individual temperature of 24.7 °C (Namara et al. 2015). The leaves (Jyothis et al. 2008) leading to decreases in second location was at Abi Zonal Agricultural 0 photosynthetic capacity and early defoliation affecting Research and Development Institute in Arua (3°04 N, the pod-filling stage (Shanower et al. 1993). Tradi- 30°560E) with an average altitude of 1215 m asl, a tionally, GLM pest is controlled by pesticide sprays mean annual rainfall of 1250 mm and temperature of during the cropping season (Okello et al. 2013), 24 °C (Sserumaga et al. 2015). These areas are however, previous studies have shown that leaf miners considered hotspot regions of groundnut leaf miner 123 Euphytica (2018) 214:192 Page 3 of 15 192 in Uganda (Okello et al. 2010; Namara et al. 2015). row was planted at a spacing of 60 9 5 cm per Thirteen soybean genotypes, obtained from the USA, genotype in each of the five blocks, replicated twice. International Institute of Tropical Agriculture (IITA) The last row in each replication consisted of a and Uganda (see Table 1 for their full description). particular genotype added in order to fit the design. These genotypes were selected based on their GLM Planting was done in the second growing season of reaction as reported by Namara et al. (2015). 2016 (September to December) the period when the pest is reported to occur under natural insect infesta- Crosses and mating design tion in two GLM hotspot locations of Iki-iki sub- county in Budaka and Abi Zonal Agricultural A full diallel mating design developed by Griffing Research and Development Institute in Arua district, (1956) was used for this study. Five seeds from each of Uganda (Namara et al. 2015). Data were recorded for the 13 parents were planted in perforated plastic pots incidence, severity and number of leaf miner larvae of diameter 25 cm and height 30 cm containing (average from 10 randomly selected F2 plants per each sterilized loam and sandy soils in the screen house at genotype) per plot at 40, 60, 70 and 80 days after the Makerere University Agricultural Research Insti- planting in order to monitor the infestation levels at the tute Kabanyolo (MUARIK), from October 2015 to different crop stages (Ramani and Lingappa 1988). April 2016. Staggered planting of parents was done to The data on GLM incidence was obtained by counting synchronize flowering and to ensure continuous the total number of leaflets and damaged leaflets from availability of flowers for crossing. Plants were 10 randomly selected plants per plot and expressed as watered after every two days until they reached percentage leaflet damage (Praveena et al. 2011). The physiological maturity. The F1 seeds were planted GLM severity was given by using a standard scale of alongside their respective parents in the screen house 1–5 (Praveena et al.