Articles

Measurement of cell membrane thermo-stability and leaf temperature for heat tolerance in maize (Zea mays L): Genotypic variability and inheritance pattern


Abstract


The rise in ambient temperature is intimidating sustainability of maize productions worldwide. To overcome heat stress effects, identification of potential genotypes and knowledge of inheritance pattern is necessary for developing thermo-tolerant cultivars. This investigation, consisted of four experiments, was conducted for assess- ing genetic variation followed by developing and evaluating breeding material in non-stressed and heat-stressed environments. The first experiment concerning reproductive stage heat tolerance comprised one hundred maize inbred lines, was conducted at mean day/night temperatures of 33°C/19°C (field) and 40°C/23°C (plastic tunnel), respectively. Variance analysis of absolute and relative data for leaf temperature and cell membrane thermo- stability revealed statistically significant (P ≤ 0.01) genotypic variations. In second and third experiments, one heat tolerant (ZL-11271) and one susceptible (R-2304-2) lines were selected and crossed in a generation mean fashion to develop non-segregating (P , P , F ) and segregating (BC , BC , F ) plant populations. The fourth experiment
involved appraisal of six basic generations in a factorial randomized complete block design replicated thrice with
mean day/night temperatures of 33°C/20°C and 39°C/24°C. Data on leaf temperature and cell membrane thermo- stability recorded at reproductive phase were analyzed in a nested block design which suggested involvement of digenic epistatic interactions in controlling inheritance of both these traits. Generation variance analysis, however, revealed predominance of additive genes supported by higher estimates [> 60%] of broad sense and narrow sense heritability (F
and F ). Future progress in plummeting leaf temperature and cell membrane thermo-stability of plant material is achievable through hybridization and rigorous selections in succeeding generations.

Keywords

heat tolerance, inheritance pattern, leaf temperature, cell membrane thermo-stability, maize

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Maydica - A journal devoted to maize and allied species

ISSN: 2279-8013