Genetics of drought tolerance at seedling and maturity stages in Zea mays L.

Abstract

Shortage of irrigation water at critical growth stages of maize is limiting its production worldwide. Breeding drought-tolerant cultivars is one possible solution while identification of potential genotypes is crucial for genetic improvement. To assess genetic variation for seedling-stage drought tolerance, we tested 40 inbred lines in a completely randomized design under glasshouse conditions. From these, two contrasting inbred lines were used to develop six basic generations (P1, P2, F1, F2, BC1F1, BC2F2). These populations were then evaluated in a triplicated factorial randomized complete block design under non-stressed and drought-stressed conditions. For statistical analyses, a nested block design was employed to ignore the replication effects. Significant differences (p≤0.01) were recorded among the genotypes for investigated seedling-traits. Absolute values of fresh root length, fresh root weight, and dry root weight lead to select two genotypes, one tolerant (WFTMS) and one susceptible (Q66). Estimates of heritability, genetic advance, and genotypic correlation coefficients were higher and significant for most of the seedling-traits. Generation variance analysis revealed additive gene action. Narrow-sense heritability [F2 ≥ 65; F∞ ≥ 79] revealed the same results. Generation mean analysis signified additive genetic effects in the inheritance of cob girth, non-additive for plant height, grains per ear row and grain yield per plant, and environmental for ear leaf area, cob length, grain rows per ear, biomass per plant, and 100-grain weight under drought-stressed conditions. For conferring drought-tolerance in maize, breeders can adopt the recombinant breeding strategy to pyramid the desirable genes.

Screening for Drought Tolerance in Maize (Zea mays L.) Germplasm Using Germination and Seedling Traits under Simulated Drought Conditions

“…Similar heritability values in seedling traits, across nitrogen level applications, were reported in maize, whereas more variation was found in adult plants [ 32 ]. This result agrees with the estimates that heritability and genotypic correlation coefficients were significantly high for most of the seedling traits in maize [ 43 ].…”

Generation Mean Analysis and Molecular Markers for Drought Tolerance in Wheat during Germination and Seedling Stage

“…However The additive-dominance along with epistatic interaction effects recorded for GP, RFW, RDW, SFW and SDW in both crosses suggested postponement of plant selections till the later generations for plant traits with such type of gene action (Iqbal et al, 2012;Khan et al, 2016). Sharmila et al (2007) and Said (2014) reported that the additive effects and gene interaction dominance x dominance (l) or other type di-genic complementary gene interaction can be exploited effectively by selection for the characters improvement.…”

Effect of PEG Induced Drought Stress on Germination and Seedling Traits of Maize (Zea mays L.) Lines

“…Therefore, biometric attributes at the early growth stages can be used as selection criteria for improving crop resistance against drought (Blum, 2011;Comas et al, 2013). It can be supported by the evidence that several germination and seedling growth indices are frequently used as predictors to screen crops for drought tolerance (Comas et al, 2013;Ayalew et al, 2014;Shamim et al, 2014;Obidiegwu et al, 2015, Khan et al, 2016Álvarez-Iglesias et al, 2017, Queiroz et al, 2019.…”