Assessment of G x E interactions and stability of baby corn hybrids for yield and yield contributing traits

Introduction

Maize is one of the world's most important annual cereal crops, cultivated on more than 200 million hectares and contributing nearly 1.24 billion tonnes to global food production in 2023-2024 (FAOSTAT, 2024). Maize breeding programmes aim to develop genotypes with high yield potential and broad adaptation. The rising demand for vegetables from both human and livestock populations has increased the need for enhanced production of baby corn. To meet these demands, newly developed inbred lines, hybrids, and open-pollinated varieties are routinely evaluated through multi-environment trials (METs). Newly developed genotypes are typically evaluated through multi-environment trials (METs) to assess their yield potential, stability and suitability for cultivation across different regions. Evaluating the performance of hybrid parental inbred lines is also crucial, as their productivity directly influences seed production efficiency and the success of commercial hybrids. METs additionally help identify testing locations that best represent the target production environments. Therefore, this study aims to investigate the genotype-by-environment interaction (GEI) effects in maize breeding to enhance the selection and development of genotypes with high yield potential and stability across different environments. Specifically, it seeks to understand the cob or grain yield performance of hybrid parental inbred lines, which is crucial for the successful production of commercial hybrids, and to identify experimental sites that best represent target environments for optimized breeding strategies

Materials and Methods

The present study was carried out to collect information on stability performance of hybrids and their parents in baby corn (Zea mays L.) over three locations. The experimental material consisted of 105 genotypes, including 75 F₁ hybrids, 28 parents and two checks (DMR-1142 and DMR-1144). The parental lines included CM-104, CM-115, CM-119, CM-201, BML-5016, BML-5118-3, BML-5160, BML-5161, BML-5219, BML-5222, BML-5342, QPM-57-1, BML-5063-1, BML-5204-3, BML-5121, BML-5212, BML-5347-2, QPM-33, QPM-63-1, BML-5204-5-2-1, BML-5207, BML-5204-1-8, QPM-49, QPM-69-2 and QPM-62, while the testers were BML-6, BML-13 and CM-131. These parents were crossed using a Line × Tester mating design to generate 75 F₁ hybrids. The study was conducted during the kharif season across three environments representing diverse agro-ecological conditions: College Farm, Rajendranagar, Hyderabad; Regional Agricultural Research Station (RARS), Jagityal, Karimnagar district; and Agricultural Research Station (ARS), Kampasagar, Nalgonda district of Telangana. The experiment at each location was laid out in a Randomized Block Design (RBD) with three replications. Each genotype was planted in a single row of 4 m length with a spacing of 60 × 20 cm (row-to-row × plant-toplant). Recommended agronomic and plant protection practices were followed uniformly across locations to ensure a healthy crop stand. A fertilizer dose of 120:80:60 kg N:P:K ha⁻¹ was applied, of which the full dose of phosphorus and potassium and half of the nitrogen were applied as basal, while the remaining nitrogen was top-dressed in two equal splits at knee-height and tasseling stages. Observations were recorded on all genotypes for the characters under study following standard procedures across all environments. The pooled analysis of variance over locations was carried out to assess genotype × environment interactions and stability performance, and stability parameters were estimated using standard statistical models appropriate for multi-environment evaluation.

Table 1: List of the maize inbred lines & crosses used in the study The pooled analysis of variance for 12 characters over three locations viz., Rajendranagar, Jagityal and Kampasagar revealed significant differences among genotypes except baby corn girth and TSS (Table -1). Genotype x Environment interaction was significant for all the characters. Environment (linear) was significant for all the characters except baby corn girth. The genotype x environment (linear) interaction was significant for days to 50 per cent tasseling, days to 50 per cent silking, plant height, baby corn length, baby corn girth and cob yield per plant. Pooled deviations were significant for days to 50 per cent tasseling, days to 50 per cent silking, baby corn length, baby corn girth, cob weight, number of cobs per plant, cob yield per plant, cob yield, green fodder yield and TSS. The G X E interactions were significant for the 12 characters. Days to tasseling is an important phrenological trait. Among lines, seven were unstable. BML-5222, CM-201, BML-5118-3, QPM-62 were early maturing with average stability, whereas BML-5160, BML-5161 were early and adapted to favourable environments (bi > 1). Testers BML-13, CM-131 showed early flowering with average stability, while BML-6 suited unfavourable environments (bi < 1). Among hybrids, 27 were unstable. QPM-62 × BML-6, BML-5121 × CM-131, QPM-69-2 × CM-131, QPM-63-1 × CM-131, QPM-33 × BML-13, QPM-49 × CM-131 were early, stable, and suitable for wide adaptability. BML-5207 × BML-6 adapted to favourable, and BML-5207 × CM-131 to unfavourable environments. Days to Silking time is critical for synchrony with tasseling. Four lines were unstable. BML-5222, CM-201, BML-5118-3, QPM-62 were early and stable; BML-5160 favored better environments. Testers BML-13, CM-131 exhibited early silking with average stability. Among hybrids, 27 were stable. BML-5222 × CM-131, QPM-62 × BML-6, QPM-69-2 × CM-131, BML-5121 × CM-131, QPM-63-1 × CM-131, BML-5207 × BML-6, CM-104 × CM-131 were early, widely adaptable. BML-5342 × BML-13 adapted to favourable, while BML-5204-1-8 × BML-6/×BML-13 suited unfavourable environments. Plant height influences biomass and light interception. All lines were stable. BML-5212, BML-5121 were tallest with average stability; QPM-62 favored better environments. Testers CM-131, BML-6 were stable. Among hybrids, nine were unstable. BML-5212 × CM-131, BML-5212 × BML-6, BML-5121 × CM-131 showed highest plant height and wide adaptability. CM-119 × BML-13 favored better environments; BML-5204-1-8 × BML-6 suited poor environments. Ear height affects lodging resistance and cob harvest. Nine lines were unstable; BML-5121, BML-5063-1, QPM-62, QPM-57-1, QPM-33 were stable. Tester BML-6 had average stability. Among hybrids, 32 were unstable. BML-5121 × BML-13, BML-5121 × BML-6, QPM-57-1 × CM-131 were widely adaptable. QPM-69-2 × BML-6 favored favourable, BML-5347-2 × BML-6 unfavourable environments. Baby corn length is a key marketable trait. Five lines were unstable. BML-5212 recorded highest length with average stability; BML-5016 favored better environments. Tester CM-131 was stable. Among hybrids, 11 were unstable. BML-5212 × CM-131 favored better environments; BML-5121 × BML-6, BML-5121 × BML-13, BML-5212 × BML-13, BML-5347-2 × BML-6 were widely adaptable; BML-5219 × BML-13, BML-5063-1 × BML-13 suited poor environments. Girth determines cob size and yield. BML-5219, BML-5204-1-8 lines were unstable. BML-5342, BML-5063-1, CM-104, BML-5204-5-2-1 were stable; QPM-57-1 favorable. Testers CM-131, BML-13, BML-6 had average stability. Among hybrids, 10 were unstable. CM-119 × CM-131, BML-5207 × BML-6, BML-5222 × BML-6 were widely adaptable; BML-5212 × BML-13 suited poor environments. Cob weight is directly related to yield. Eleven lines were unstable. BML-5212, BML-5219, QPM-63-1 stable; BML-5347-2 suited poor environments. Testers BML-13 stable, CM-131 favorable. Among hybrids, 30 unstable. BML-5212 × BML-6, BML-5121 × CM-131, BML-5212 × CM-131 widely adaptable; BML-5121 × BML-6 favourable. Number of cobs per plant contributes to total yield. Eleven lines unstable. QPM-63-1 stable; BML-5063-1, BML-524-3, BML-5118-3 suited poor environments. Tester BML-6 stable. Among hybrids, 62 unstable. QPM-57-1 × CM-131, CM-115 × CM-131, BML-5219 × BML-6, QPM-57-1 × BML-13, BML-5063-1 × CM-131 widely adaptable; QPM-63-1 × BML-13 favorable. Cob yield per plant reflects productivity. Nine lines unstable. BML-5212, QPM-63-1, BML-5204-3, BML-5161, BML-5219 stable. Tester BML-13 poor environment, CM-131 stable. Among hybrids, 38 unstable. BML-5121 × BML-6, BML-5016 × CM-131, QPM-57-1 × CM-131, BML-5161 × BML-6, CM-119 × BML-13 widely adaptable; BML-5204-3 × CM-131 favorable; QPM-62 × BML-6 unfavourable. Cob Yield per Hectare for Lines: 16 unstable. BML-5212, BML-5219, BML-5347-2 stable. Tester BML-13 poor, CM-131 stable. Hybrids: 19 unstable. BML-5212 × CM-131, BML-5212 × BML-6, BML-5121 × BML-6 widely adaptable; BML-5219 × BML-13 favourable. Green fodder yield for Lines: three unstable. BML-5212, BML-5219, BML-5016 stable. Tester CM-131 poor, BML-6 stable. Hybrids: 32 unstable. BML-5212 × CM-131, BML-5212 × BML-6, BML-5212 × BML-13 widely adaptable; BML-5204-3 × BML-13 favorable. TSS content influences baby corn quality. Eight lines unstable. BML-5212 highest; BML-5222, BML-5347-2, CM-104, CM-119, QPM-33 stable. Tester CM-131 poor; BML-6 average stability.

Acknowledgement

AcknowledgementWe wholeheartedly acknowledge the support in terms of fund and guidance given by faculty at College of Agriculture, Rajendranagar, Hyderabad. Regional Agricultural Research Station Jagtial, Karimnagar and Agricultural Research Station, Kampasagar, Nalgonda

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