Variability, heritability and physiology of drought resistance in a breeding population of creeping bentgrass (Agrostis stolonifera)

In the spring of 1995 a study was initiated to determine variability, heritability and physiology of drought resistance in an advanced breeding population of 28 creeping bentgrass clones. Characters measured to determine the extent of variability in response to drought were: leaf water potential, leaf osmotic potential, leaf turgor potential, plant color, plant quality and percent live tissue. Variability in drought resistance was observed within the population for leaf water, osmotic and turgor potential, plant color and quality. Narrow sense heritability of plant color, quality and percent live tissue was determined from a sub-group of 12 of the clones and their half-sib progeny. Narrow sense heritability ranged from 0.96-1.0 for each of the characters measured. Plants were selected that ranked in the top and bottom 10% for drought resistance and subjected to analysis of leaf water relations before and after stress. Characters measured included relative water content, leaf water potential, and appoplastic water content at zero turgor, leaf osmotic potential at full turgor, bulk modulus of elasticity, and turgid weight/dry weight ratios. Osmotic adjustment was not observed among clones. Elasticity was different among plants that ranked highest and lowest for drought resistance, indicating that increased elasticity is a mechanism of drought resistance in select creeping bentgrass clones.