Maize the third most vital cereal crop globally. Though, little of this maize is eaten directly by humans; but, it is the significant staple food in Sub-Saharan Africa. Unfortunately; maize output in has been badly affected by drought. Therefore; steps should be taken to enhance to maize production under arid and semi-arid conditions through genetic engineering. Drought tolerance is a complex characteristic; which is controlled by polygenes and their expressions are influenced by various environmental factors1,2. To produce hybrid drought tolerance maize plants is not an easy task for plant breeders because of less heritability of grain yield and the complications of genotype-environment connections. On the other hand; secondary traits have relatively high genetic variance and heritability3,4. Therefore; secondary traits linked to grain yield are being utilized with grain yield to select drought tolerant maize genotypes5,6.
But, the effectiveness of secondary traits for indirect selection for grain yield is not well-known due to the nature of the genetic material and circumstances of experiments. Consequently; there is need to determine the value of a secondary trait before performing investigation7. Abdalla Dao and team designed a study to evaluate the most suitable secondary characters for selection index to choose maize drought tolerant varieties. Thus, broad-sense heritability of the traits and phenotypic correlations were computed. Path coefficient analysis was used to determine the direct and indirect effects. For this purpose, 48 testcross hybrids derived from lines with different genetic background and geographical origins plus 7 checks were assess in both well-watered and water-stressed conditions for over two years for grain yield and secondary traits to decide the most proper secondary traits and select drought resistant plants.
Scientists recognized ear per plant, tassel size and plant recovery as imperative indirect selection criteria for grain yield under drought conditions. The efficacy of ASI, LR, LS and LE as indirect selection traits for grain yield under drought stress were not verified in this research. The path coefficient analysis exhibited that the traits identified as useful secondary traits were considerably linked to grain yield. However, their direct impact on grain yield were little or had central involvement in grain yield through other characters. Therefore, these traits should also be considered in selection for drought tolerance.
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21 August, 2019