Thumbnail Image

Thesis

Browse

20131
Reset filters
Subject: Plant Breeding × Author: goyal × End date: 2013 × Start date: 2010 × Type: Thesis × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    Genetic analysis of hydrocyanic acid, water use Efficiency and quality traits over senvironment in forage sorghum [Sorghum bicolor (L.) Moench]
    (Punjab Agricultural University, Ludhiana, 2013) goyal
    The present investigation was undertaken in the Department of Plant Breeding & Genetics, Punjab Agricultural University, Ludhiana during 2010-2013 to study the genetic analysis of hydrocyanic acid (HCN), water use efficiency (WUE) and quality traits over environments viz. normal environment (Env-N) and water stress environment (Env-S) in forage sorghum [Sorghum bicolor (L.) Moench]. Under experiment-1, evaluation of 60 top crosses obtained from crossing 15 cms lines to four populations as males was done. Analysis of variance for green fodder yield and its component characters, HCN and traits affecting WUE revealed significant differences due to genotypes, environments and significant genotypic x environment interaction for most of the traits. The analysis of variance for combining ability suggested that the variance due to general combining ability (gca) and specific combining ability (sca) were significant and varied with the change in environment for important traits. The estimates of 2gca and 2sca indicated the predominance of non-additive gene action in the inheritance of all the traits. The cms lines, AKMS-14A, 2077A, NSS1007A and NSS1008A under Env-N and 940031A and NSS1008A under Env-S were good general combiners for green fodder yield and its component characters, low HCN content and high water use efficiency. With respect to green fodder yield, population RSSV-9 appeared to be the best general combiner under both the environments. One top cross 94002A x RSSV-9 had high sca effects for these traits in both the environments. Estimation of heterosis showed that three crosses viz. 94002A x RSSV-9 (54.15% and 27.25% under Env-N and Env-S, respectively), AKMS-14A x RSSV-9 (52.26% and 25.27% under Env-N and Env-S, respectively) and NSS1007A x Ramkel (48.49% and 7.69% under Env-N and Env-S, respectively) manifested significant positive heterosis over PSC-1 for green fodder yield and significant negative heterosis for HCN under both the environments. The selections for high green fodder yield under both the environments could be carried out by phenotypic selection for early vigour, plant height, leaf area index, photosynthetic capacity and proline content in the desired population. Under experiment-2, 100 families of each type viz. full sib, half sib and S1 were evaluated under two already mentioned environments. The trend for mean fodder yield and yield contributing traits viz. plant height, number of leaves per plant and leaf area index and HCN showed that the mean of full sib families exceeded the mean of half sib families and mean of S1 families. This indicated that the heterosis and inbreeding depression were important for these traits in this population. The green fodder yield and its components and traits affecting water use efficiency had 2A*/2A greater than 0.5 in both the environments. This suggested more contribution of additive gene effects than dominance effects for genetic control of green fodder yield and other important characters. For HCN content, the ratio of 2A*/ 2A was less than 0.5 in Env-N and greater than 0.5 in Env-S which suggested that dominance and/ or epistasis were more influential in controlling HCN content under Env-N. Additive genetic variation estimated appeared to be sufficiently great to permit substantial progress by any of the three family systems of selection, but S1 family selection appeared to be the most promising, particularly for improving green fodder yield, yield components, HCN content and WUE traits.