Wednesday, 9 November 2005
8

This presentation is part of: Physiology: V

Genetic Variability for Physiological Traits Related to Water Use Efficiency in Sorghum.

Maria Balota, William Payne, Satish R. Ambati, William Rooney, and Darrell Rosenow.

There is an increasing need to improve water use efficiency (WUE) of the crops under water-limited and irrigated environments. WUE is basically defined as total biomass produced per unit water consumed. Gas exchange efficiency, defined as the ratio of photosynthesis to transpiration (A/E), has been demonstrated to be a good estimate of the WUE at the canopy level in grain sorghum. A controlled environment study was conducted to evaluate A/E and WUE in twelve F1 hybrids resulting from a 4 x 4 diallel crossing pattern. The parents, TX430, TX7078, SC414 and R9188, were evaluated prior to this experiment under dryland field condition and chosen based on their contrasting A, E, and A/E. Significant differences for A, E, A/E, and WUE were found among the hybrids and their parents. TX7078 and all its hybrids showed the highest A and E values, and the lowest A/E ratios. TX430 and its hybrids produced high A and low E values, therefore these genotypes had high A/E values. The slopes of A regressed by E estimated that TX430 and its hybrids assimilated approximately 30% more carbon per unit water transpired than TX7078 and its F1's. With few exceptions, WUE correlated well with the A/E ratios. Genetic analyses of general and specific combining ability will be presented.

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