ROOTING CAPABILITY AS IT RELATES TO SOIL MOISTURE EXTRACTION AND OSMOTIC POTENTIAL OF SEMIDWARF AND NORMAL-STATURED GENOTYPES OF SIX-ROW BARLEY (HORDEUM VULGARE L.)
The rooting capabilities of four semidwarf and two normal-statured genotypes were estimated by 32P uptake and extraction of roots from a column of soil. The two height groups did not differ in root volume when the plants were grown in a rooting medium composed of three parts sand and one part topsoil. Rooting was estimated under field conditions by placing 32P in the soil at 15, 30, 60, and 90 cm and measuring 32P activity in the aerial plant portions 15, 30, 45 and 61 days from seeding. Semidwarf and normal-statured types had the same relative distribution of 32P uptake on all days. Water uptake by semidwarf and normal height genotypes was similar over the season in both environments receiving incident rainfall. There was a significant effect of environment on the osmotic potential of the last fully developed leaf. Plants growing in environments with low soil water developed lower osmotic potentials. However, there were no differences in genotypic reponse indicating similar osmotic adjustment. It was concluded that semidwarf and normal genotypes do not differ in rooting water uptake or osmotic adjustment due to plant stature.