Jehanzeb Farooq¹ , Ihsan Khaliq² , Abid Mahmood³

1. Cotton Research Institute, Ayub Agricultural Research Institute, Faisalabad, Pakistan 2. Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad, Pakistan 3. Director General Agri. Research Ayub Agricultural Research Institute, Faisalabad, Pakistan
Author    Correspondence author
Triticeae Genomics and Genetics, 2014, Vol. 5, No. 2   doi: 10.5376/tgg.2014.05.0002
Received: 30 Nov., 2014    Accepted: 30 Dec., 2014    Published: 26 Jan., 2015

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Farooq and Khaliq, 2014, Evaluation of Some Wheat Hybrids under Normal and Heat Stress Conditions, Triticeae Genomics and Genetics, Vol.5, No.2 1-11 (doi: 10.5376/tgg.2014.05.0002)

Heat shocks at anthesis are one of the major limitations in wheat productivity in many countries worldwide including Pakistan. Present investigations were designed to battle out this calamity which may further be exploited in breeding heat tolerant cultivars. Seven parents including tolerant, moderately tolerant and susceptible but high yielders were utilized for this purpose and later hybridized in a 7 ×7 diallel fashion. Analysis of variance revealed significant variability for all the parameters studied. Highest value of negative and desirable significant heterosis and heterobeltiosis for plant height was shown by the cross combinations Weebli-1 × Uqab-2000, Inqilab-91 × Shalimar-88 under normal conditions and under stress by the hybrids Uqab-2000 × Weebli-1, Shalimar-88 × Maya/Pavon. Maximum positive heterosis for tillers per plant was recorded by the cross combination Shalimar-88 × Chenab-2000 (12.04%) and maximum positive and highly significant heterobeltiosis was recorded by the cross combination Shalimar-88 × Chenab-2000 (11.46%). Under stress for tillers per plant none of the crosses showed positive estimates. Maximum positive heterosis for 100- grain weight was shown by the cross combination Chenab-2000 × Inqilab-91 (28.22%). Maximum positive heterosis under stress for 100-grain weight was shown by the cross Inqilab-91 × Weebli-1 (23.35%) followed by Chenab-2000 × Inqilab-91 (22.22%). Maximum positive heterosis for grain yield under normal conditions was manifested by the cross combinations Uqab-2000 × Punjab-85 (28.70%) and under stress maximum positive heterosis was recorded by cross combination Shalimar-88 × Uqab-2000 (27.02%).  The results of heterosis and heterobeltiosis estimation revealed that the hybrid vigor is available in the current experiment for all the traits and selection of desirable hybrids is the best way to improve the grain yield of bread wheat. Many cross combinations in the current studies may be utilized following pedigree or bulk method to develop heat tolerant wheat varieties because of their ability to perform well under normal and heat stress conditions.

Terminal heat stress; Heterosis; Bread wheat; Cereals; Pakistan