Combining ability, heterosis and phenotypic stability for yield and other desirable characters in high quality protein maize (Zea mays L.)
Loading...
Date
2010-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation was conducted during Kharif, 2009 at Norman E. Borlaug Crop Research Centre, Pantnagar under normal (recommended dose of nitrogen, E1), low-nitrogen(E2) and excess soil moisture (E3) environments with the objectives: (i) to identify superior single cross quality protein maize (QPM) hybrids, (ii) to determine nature and magnitude of heterosis, (iii) to estimate variability parameters, combining ability and phenotypic stability of parental inbreds and hybrids for important economic characters in quality protein maize (QPM). The experimental material consisted of 21 QPM inbred lines and 3 broad-base testers crossed in a line x tester fashion. All the 24 parents, 63 F1’s along with three checks HQPM-1, Shakti-1 and Pragati, were evaluated in a randomized complete block design. Observations on 15 characters, like plant height, ear height, 100-kernel weight, ear length, ear diameter, number of kernel rows/ear, number of kernels/row, number of nodes bearing brace roots, days to 50% tasselling, days to 50% silking, anthesis-silking interval, protein, tryptophan and lysine contents and grain yield were recorded. Analysis of variance revealed that these genotypes differed significantly for all the 15 characters, indicated the presence of sufficient amount of variability among genotypes. As regards heterosis, high per cent heterobeltiosis, standard heterosis and relative heterosis in all the three and pooled over environments was observed in crosses, L1×T1 (DQPMC-3(Y)_101-1-2-1-1×DMRQPM-03-106-#-_-1-1-1), L2×T1 (DQPMC-3(Y)_101-1-2-1-1×DMRQPM-03-103-#-_-2-1-1-1), L10×T1 (DQPMC-3(Y)_50-1-1-1-1×DMRQPM-03-106-#-_-1-1-1-1), L11×T3 (Pool 18C8(TEYFQPM)-B-9-1-1-1×Pool17C8(TEYFQPM)-B-57-2-1-1) and L14×T1 (DMRQPM-28-5-_-_-#-_3-_-1-1-1× DMRQPM-03-106-#-_-1-1-1) for grain yield. High estimates of heritability were observed for quality traits, 100-kernel weight and grain yield in all the three environments, whereas, high estimates of expected genetic advance as per cent of mean were recorded for grain yield and quality characters, under all the environments. Combining ability analysis revealed significant variances due to GCA and SCA for most of the characters in all the three environments indicating importance of both additive and non-additive genetic variances. The magnitude of SCA variance was greater than GCA variance for all the characters in all the environments showing preponderance of non-additive variance and suitability of material for hybrid breeding. The GCA effects of the parents indicated that parental lines, L1, L2, L3, L4 in E1; L1, L3, L4, L11, L12, L13, L14 and L16 in E2; L8, L4 and L7 in E3 and L1, L2 and L4 in pooled environment and testers, T1 and T3 in over all environments, were the best combiners. The maximum SCA effects were observed in crosses, L11×T3, L14×T1 and L3×T1 in E1, L11×T3, L17×T3 and L1×T1 in E2, L11×T3 in E3 and L11×T3 and L17×T3 in pooled environment for grain yield and its contributing traits as well as for quality traits. The pooled analysis of variance for phenotypic stability indicated that mean squares due to genotypes and environments were significant for most of the characters. It indicated substantial variability among genotypes and environments. G×E interaction was also highly significant for all the traits except quality characters. Among the 21 lines and 3 testers, L1, L4, L6, L10, L12, T1 and T2 showed desirable stability for grain yield and its components along with quality characters. Out of 63 single crosses, most desirable and stable were L2×T3, L3×T3, L5×T2, L5× T3, L7×T1, L7×T3, L8×T1, L8×T2, L8×T3, L9×T3, L10×T1, L10×T2, L11×T2, L11×T3, L12×T1, L12×T3, , L13×T3, L14×T3, L16×T2, L16×T3, L17×T2, L17×T3, L20×T2, L20×T3, L21×T1, L21×T2 and L21×T3 for grain yield. However, L1×T1, L1×T3, L2×T1, L2×T2, L3×T3, L4×T3, L6×T3, L8×T2, L10×T2, L10×T3, L11×T1, L14×T2, L15×T1, L16×T1, L16×T2, L16×T3, L17×T3 and L20×T3 were found to be desirable and stable for quality traits. For rich environment, L1, L2, L4, L9, L13 and L21, tester, T1 and T2 and crosses, L1×T1, L2×T1, L4×T3, L6×T1, L7×T3 and L11×T1 showed stable and desirable performance. However, under poor environment, L1, L8, L9, L13, L14 and L17, tester, T1 and T3 and crosses, L4×T2, L5×T2, L7×T2, L18×T3 and L19×T2 exhibited stable and desirable performance for grain yield and its contributing traits. While, for quality characters no specific cross was found good under both rich and poor environment.
Description
Thesis-PhD
Keywords
combining ability, heterosis, phenotypic stability, yield increases, crop quality, proteins, maize, Zea mays