Evaluation of maize (Zea mays L.) inbred lines under heat stress and normal condition

Masters Thesis from the year 2018 in the subject Biology - Botany, grade: A, language: English, abstract: Twenty maize genotypes were tested in alpha-lattice design with two replications in research block of National Maize Research Program, Rampur, Chitwan from February to June, 2016 to evaluate maize inbred lines for their genetic components association among yield components and correlation and stress tolerance indices. Shorter ASI was found in RML-17, RML-57, RL-107, RL-140, RML-91 whereas more leaf area index in NML-2, RML-91, and RML-24 respectively. Inbred lines, RML-91, RML-17, RML-20, RL-140, RL-140, RML-91 and NML-2 were found lower tassel blast and leaf firing percentage respectively. Inbred lines, RML-76, RML-115, RML-4, RL-111 showed slower leaf senescence and RML-57, RL-101, RML-11, RL-107 showed significant higher value of SPAD chlorophyll content. Heritability and correlation analysis revealed that grain yield, number of kernel ear-1, silk receptivity, shelling percentage, thousand kernel weight plant and ear heights showed presence of additive gene effect and those traits direct could be used as direct selection to improve maize grain yield under heat stress condition. With attention to high negative correlation with anthesis silking interval, tassel blast, leaf firing with grain yield the minimum of anthesis silking interval, tassel blast and leaf firing were the most important index required further genotyping for development of thermo-tolerance lines. Cluster and PCA analysis revealed that cluster 4 genotype named as RL-140, RML-76, RML-40 and RML-91 were found to be tolerant to heat stress with higher value of grain yield and other desirable traits and lower leaf firing, Tassel blast and itermediate of anthesis-silking interval which were suitable for cultivation under heat stress condition.Based on stress tolerance indices and their correlation analysis, RML-91, RML-140 appeared as having high yield potential and low stress susceptibility u