The Potential for Exploiting Variation in Salinity Tolerance in Pearl Millet (Pennisetum americanum (L.) Leeke)

Abstract

AbstrctShoot and root growth and plant dry weight were determined for twenty four accessions of pearl millet, Pennisetum americanum (L.) Leeke, after two weeks growth in saline solution culture at EC 20 dS m‐1. The EC was achieved using NaCl + CaCl2 1:1 by weight in solution culture. Although salinity markedly inhibited growth of all accessions, three, 93613, KAT/PM‐2 Kitui, and Kitui local produced significantly greater dry matter, and they and 93612 had longer shoots than the other accessions. Accessions WCA 78 and Bulk 7704 were highly sensitive to salinity in all 3 characters measured. There was considerable variation between the 24 accessions, suggesting that selection for increased tolerance to salinity in pearl millet should be possible. This was examined using normal seed of the cultivar Al/3. A first cycle of selection screened 16,000 seeds after 15 days growth in nutrient solution at EC 26 dS m‐1. 106 individuals were selected to form the S1 selection line. Selected seedlings were grown to maturity and polycrossed.In a second cycle of selection, 30,000 S1 polycross progeny were screened as previously, but at EC 30 dS m‐1. A selection intensity of 0.08% was achieved. The selected plants were again grown to maturity and again polycrossed.Efficiency of the selection procedure was assessed from comparison in sand culture of the performance of the selected line with the unselected Al/3 line and Kitui local which from the previous assessment of the 24 accessions was rated as relatively salinity tolerant. The selection line was superior to the other two lines at four salinity levels. The results of this study suggest that further improvement in salinity tolerance in pearl millet may be expected from further selection and breeding, using the methods described here.