COMPARISON OF TESTS CHARACTERIZING VARIETIES OF BARLEY AND WHEAT FOR MOISTURE STRESS RESISTANCE

Abstract

The tiller survival test was used to characterize eight cultivars of wheat (seven of Triticum aestivum L. and one of Triticum durum Des. F.), and seven cultivars of barley (four of which were Hordeum vulgare L. and three Hordeum distichon L.) for moisture stress resistance. Several avoidance and tolerance tests were then assessed for their effectiveness in characterizing the cultivars for moisture stress resistance in relation to the survival test. Of the avoidance tests, visual wilting correlated well with tiller survival but the water loss from leaves and stomatal diffusion resistance tests did not. Of the tolerance tests, root weight under moisture stress showed a good relationship with survival; root weight without moisture stress correlated well with survival for wheat and somewhat less for barley. A comparison of root and leaf weight in two soils differing in moisture-holding ability was useful but less correlated with survival. An unsatisfactory tolerance test was germination in mannitol as there was no correlation in rankings with drought survival. Two semi-dwarf wheat cultivars, Pitic and Fielder, and the two-rowed barley cultivars Nordal and Volla demonstrated the greatest moisture stress resistance. This study of avoidance and tolerance tests leads us to the conclusion that no one test, used singularly, has sufficient reliability to determine overall cultivar drought response in wheat and barley. At least one test measuring avoidance and one measuring tolerance should be used.