doi:10.14720/aas.2019.114.1.6 Original research article / izvirni znanstveni članek Performance of popcorn introductions for agronomic characters, grain yield and popping qualities in the forest and derived savannah agro-ecologies of Nigeria Oloruntoba OLAKOJO 1, 2, Gbadebo OLAOYE 1, Adewole AKINTUNDE 3 Received April 25, 2019; accepted August 14, 2019. Delo je prispelo 25. aprila 2019, sprejeto 14. avgusta 2019. Performance of popcorn introductions for agronomic char- Predstavitev uspešnosti uvajanja pokovke na osnovi njenih acters, grain yield and popping qualities in the forest and de- agronomskih lastnosti, pridelka zrnja in kakovosti nabreka- rived savannah agro-ecologies of Nigeria nja v gozdnih in prehodno-savanskih agroekosistemih Nige- Abstract: The study focus on the evaluation of popcorn rije lines for their yield and agronomic potentials. Genetic materi- Izvleček: Raziskava je bile osredotočena na ovredno- als were evaluated under irrigation in a three-replicate in a Ran- tenje linij pokovke glede na njen pridelek in agronomske domized Complete Block Design (RCBD) with a commercial lastnosti. Genetski material je bil ovrednoten ob namakanju variety as check. Two seeds were planted per hole using two- v naključnem bločnem poskusu s tremi ponovitvami v prim- row plots of 5 m long with inter and intra-row spacing of 0.75 m erjavi s komercialno sorto. Po dve semeni sta bili posejani v x 0.5 m, respectively in two locations viz: Ibadan and Ikenne vrstah na ploskvah dolžine 5 m, z medvrstno razdaljo 0,75 m representing the forest and savannah agro-ecologies of Nige- in znotrajvrstno razdaljo 0,5 m, na lokacijah Ibadan in Ikenne, ria respectively. Genotypes (G) differed significantly (ρ ≤ 0.01) ki predstavljata gozdne in prehodno savanske agroekosisteme for almost all the characters measured except for ear aspect. Nigerije. Genotipi (G) so se značilno razlikovali (ρ ≤ 0.01) v Location (L) as well as G x L interaction effects were also well skoraj vseh merjenih lastnosti z izjemo storža. Vplivi lokacije pronounced on all agronomic characters measured except for (L) kot tudi medsebojni vpliv lokacije in genotipa so se dobro days to silking and ears per plant. Popcorn 33-1-Y, large pearl izrazili v vseh merjenih agronomskih lastnostih z izjemo dni shaped, Popcorn 40-Y and Popcorn 34-Y were high yielding do lasenja in števila storžev na rastlino. Linije pokovke Pop- with a potential of above 2.0 t ha−1. These materials were found corn 33-1-Y, Large Pearl Shaped’, Popcorn 40-Y in Popcorn to be fairly resistant to major foliar diseases of the tropical hu- 34-Y so imele velik pridelek, s potencialom čez 2.0 t ha−1. Te mid ecologies. They are recommended for further evaluation linije so bile tudi sorazmerno dobro odporne na večino listnih across different agro-environments for possible propagation by bolezni, značilnih za vlažne tropske razmere. Priporočamo jih popcorn farmers in Nigeria to boost production. za nadaljne ovrednotenje v različnih pridelovalnih okoljih za Keywords: grain yield; introductions; popcorn; popping; nadaljne razmnoževanje pri pridelovalcih pokovke v Nigeriji za forest; derived; savannah; Nigeria povečanje njene pridelave. Ključne besede: pridelek zrnja; introdukcija; pokovka; nabrekalne lastnosti; gozd; prehodna savana; Nigerija 1 University of Ilorin, Department of Agronomy, Nigeria 2 Corresponding author, e-mail: [email protected] 3 Obafemi Awolowo University, Institute of Agricultural Research and Training, Nigeria Acta agriculturae Slovenica, 114/1, 53–60, Ljubljana 2019 O. OLAKOJO et al. 1 INTRODUCTION variability among the hybrids for popping quality traits (flake volume, popping fold, unpopped kernels and grain Popcorn (Zea mays L. everta) is a special type of flint moisture) which indicated prospect for selection of hy- maize that has the ability to pop into consumable flakes brids with good popping ability. They further reported when heated due to the thickness of the endosperm. The preponderance of additive gene action for all popping kernel pops upon heating as a result of the unique quality quality traits, thereby creating an opportunity to effec- of the endosperm that makes it resist the steam pressure tively improve these traits through selection. generated until it reaches explosive proportion (Acquaah, The initial step in achieving improvement in pop- 2007). It is one of the most widely used groups of maize corn yield and quality attributes is to evaluate the existing all over the world including in Nigeria (Mani and Dadari, germplasm for their agronomic performances and yield 2003). Its demand has increased sharply from mid-sev- potentials as well as popping attributes. The objectives of enties, stimulating production of the crop in some areas this study therefore, were to: (i) assess 19 popcorn lines of the Nigeria’s savannas and few other metropolitan cit- for yield, phenotypic attributes, reaction to prevailing ies (Iken, 1993). Popcorn varieties exist in various sizes pests and diseases and (ii) identify superior lines that and colour, it yields are lower, usually about half that of could be used for the development of commercial hy- maize hybrids (Ziegler et al., 1984) which may be as a brids for the popcorn industry, thus enhancing popcorn result of the small kernel size or its mass. productivity. Popcorn growth requirements are similar to those for dent corn and the cultural practices for both breed of corn are the same except for some minor modifications 2 MATERIALS AND METHODS in respect of popcorn. Ziegler (2001) noted that such modifications may have to do with timely planting due The experimental materials which comprised nine- to the slow germination of popcorn and harvest maturity teen (19) popcorn lines and a commercial variety as to enable optimum popping ability. Broccoli and Burak check (Table 1) were evaluated under irrigation using a (2004) reported high significant differences (ρ ≤ 0.01) Randomized Complete Block Design (RCBD). The plot for all characters evaluated except kernel density before size was two (2) rows, 5 m long with inter and intra-row expansion among fourteen (14) popcorn hybrids evalu- spacing of 0.75 x 0.5 m, respectively, replicated three (3) ated in two years across three environments. Genotype x times. The trials were established using two (2) seeds per Environment (G x E) interaction was also observed to be hole at two (2) locations viz: Ibadan (Longitude 7022’N significant for the two main traits (yield and expansion Latitude 3050’E) and Ikenne (Longitude 6053’N Latitude volume) while the relationship between grain yield and 3042’E). Fertilizer application was carried out 3 weeks expansion volume was negative. However, a strong and after planting (WAP) at the dosage rate of 180 kg ha−1 positive association was observed between expansion of NPK 20-10-10 and was top-dressed with 100 kg ha−1 volume and kernel thickness, suggesting that this trait of urea 2 weeks before anthesis. Weed control was done can be taken as a morphological variable which influence chemically with the application of 5 l ha−1 pre-emergence the expansion volume. herbicides (5 grams per litre Metolachlor and 170 grams Oz and Kapar (2011) also evaluated 18 single cross per litre Atrazine a.i). Two supplementary hoe-weedings popcorn hybrids and four commercial popcorn cultivars at 6 and 10 WAP, respectively were carried out to keep for yield and quality traits over three cropping seasons the field clean of weeds. Agronomic data and disease rat- (2006, 2007 & 2008). They reported that the genotypes ing (under natural infestation) were recorded on each differed significantly (ρ ≤ 0.01) for grain yield, plant line from each replication. Data on days to tasseling and height, tasseling time, grain moisture, % of unpopped silking; plant and ear aspects as well as husk cover using kernel and popping volume. The study identified 10 sin- 1-5 rating where 1 = excellent, 2 = very good, 3 = good, gle cross hybrids (‘TCM-05-01’, ‘TCM-05-02’, TCM-05- 4 = fair and 5 = poor, were collected on whole plot ba- 03, TCM-05-04, TCM-05-05, TCM-05-06, TCM-05-09, sis. Plant and ear heights (cm) were based on the mean TCM-05-10, and TCM-05-12) with high grain yield and of measurements collected from five random plants in a quality traits superior to those of their commercial culti- plot while grain yield was estimated from cob mass/plot vars. In their own study, Derera et al., (2014) investigated (kg) and later converted to t ha−1 after adjusting to 12 % the popping ability of 119 F1 hybrids and one standard moisture content. Diseases scored included streak, rust, check using two popping methods viz: microwave and blight, curvularia and infestation of armyworm insects, hot air methods. Although the study revealed that pop- using a rating of 1-5, where 1 = 1-10 % infection, 2 = 11- ping quality does not depend on the method adopted 29 % infection, 3 = 30-45 % infection, 4 = 46-60 % infec- for popping, the authors reported significant (ρ ≤ 0.01) tion and 5 = 61 % and above infection respectively. Data 54 Acta agriculturae Slovenica, 114/1 – 2019 Performance of popcorn introductions for agronomic characters, grain yield ... forest and derived savannah agro-ecologies of Nigeria Table 1: List of popcorn lines and their source analyses of variance (ANOVA) for agronomic characters in S/N Materials Grain colour Source the 19 popcorn lines showed that expression of almost all the characters differed significantly (ρ ≤ 0.01) from one lo- 1. Small Pearl Shaped Yellow IAR&T cation (L) to the other except days to silking and ears/plant 2. Popcorn 2-S0 Yellow IAR&T while the genotype (G) differed significantly (ρ ≤ 0.01) for 3. Popcorn 34-Y Yellow IAR&T all the characters except ear aspect and cob length (Table 4.