Assessment of Genetic Diversity among Maize Hybrids under Two Different Irrigation Conditions by Using SSR Markers, Drought Indices and Thermal Image

Authors

  • Mohamed A. Emam Agronomy Department, Faculty of Agriculture, Suez Canal University, 41522 Ismailia, Egypt.
  • Samah A. Sabrey Department of Agricultural Botany, Faculty of Agriculture, Suez Canal University, 41522 Ismailia, Egypt.
  • Osama M. Ghanem Soil and Water Department, Faculty of Agriculture, Suez Canal University, 41522 Ismailia, Egypt.
  • Amal M. Abd ELMageed Department of Agricultural Botany, Faculty of Agriculture, Suez Canal University, 41522 Ismailia, Egypt.

Keywords:

Maize hybrids, Drought, Tolerance Indices, SSR, thermal images

Abstract

The aim of the study was screened fourteen hybrids of maize; S.C.10, S.C.128, S.C.131, S.C.162, S.C.167, S.C.168, S.C.176, S.C.177, pioneer 3444, T.W.C.321, T.W.C.324, T.W.C.353, T.W.C.360 and T.W.C.368 under normal and drought stress; 100% and 50% of Field Capacity (FC) respectively. A field trial was carried out during two summer seasons 2019 and 2020 on an experimental farm, Faculty of Agriculture, Suez Canal University; Ismailia, Egypt. Several growth, yield physiological traits have been estimated. Indices of drought resistance were calculated for each hybrid; mean productivity, drought susceptibility index, tolerance index, geometric mean productivity and yield stability index (MP, DSI, TOL, GMP, and YSI respectively). Simple sequence repeat analysis of DNA (SSR) was applied to estimate the genetic differentiation among the hybrids. Results showed that corn yields were significantly reduced during drought conditions. Maize hybrids exhibited significant differences for physiological and quantitative traits; plant height, number of leaves, ear height, ear diameter, ear length, RWC and chlorophyll content. In this study the hybrids divided successfully into four groups according to their drought tolerance and yield production by using drought resistance indices. One of these groups; S.C128, S.C162, S.C167 and S.C176 hybrids had the highest yield under both conditions and more adaptive under drought stress. The results of the SSR analysis showed that polymorphism % was ranged from 50% to 67% with an average 58.5%, while polymorphism information content (PIC) values were
ranged from 0.32 to 0.57. Genetic similarity coefficient values were ranged from 0.625 to 1 with an average 0.8125. The dendrogram divided the studied hybrids into five main clusters. The study concluded that SSR analysis and drought indices results are quite similar, even though some variations in classes of hybrids regarding tolerance indices. It might be due to grain yield trait was more affected 
by drought conditions over genetic material. Thermal images were more effective for selecting maize hybrids for drought stress. Consequently; we recommended it to use in plant breeding experiment.

Published

20.10.2022