GENETIC-VARIATION IN THE ABILITY OF DETACHED AND PARTIALLY DEHYDRATED LEAVES OF RICE TO ACCUMULATE ABSCISIC-ACID, MEASURED BY RADIOIMMUNOASSAY

Variation in the ability o) 60 rice (Oryza saliva L.) varieties and three wild species to accumulate abscisic acid (ABA) in response to drought stress, drought‐induced ABA accumulation (DIAA), was assessed using a standard detached‐leaf lest. The range in DIAA amongst these genotypes was compared with the range amongst F2 plants and F6, lines derived from the O. saliva cross ‘IR20’ב63–83’ which were selected through several generations solely on the basis of differences in DIAA. ABA was measured by radioimmunoassay (RIA) or by gas chromatography (GC). DIAA in the 60 varieties was normally distributed with a six‐fold range, from 245 to 1580 ng g−1 FW. Wild species varied two‐fold in DIAA, from 375 to 889 ng g−1 FW. DIAA in F2 plants from the ‘1R20’ב63–83’ cross was also normally distributed. The extremes of DIAA for the low‐ABA and higb‐ABA F6 lines (330 and 1435ng g−1 FW) were similar to those for the varieties. Measurements by RIA and GC gave similar results. These findings are discussed in the context of producing further sets of closely‐related genotypes with similar leaf areas to study the association between DIAA and water‐use efficiency. Copyright © 1990, Wiley Blackwell. All rights reserved