STOMATAL DENSITY, APERTURE INDEX AND THEIR DIFFERENTIALS IN WHEATS (TRITICUM-SPECIES) AT LOW AND HIGH-TEMPERATURES

The material consisted of 20 promising varieties of wheat belonging to bread wheat (Triticum aestivum L emend. Fiori & Paol.), macaroni wheat (T. durum Desf.) and emmer wheat (T. dicoccum Schubl.). All these were sown on 6 dates at Parbhani during 1987-88, 1988-90 and 1989-90. The genotypes showed significant differences in all stomatal characters like stomatal density. aperture index and their differential. For stomatal aperture index, 'Hindi 62' showed the highest aperture index, followed by 'C 306', 'Khapli', 'PBN 1626', 'HD 2189', 'HI 11 84', 'PBN 1642'. 'AKW 381' and 'PBN 1627'; and the lowest by 'PBN 1445' on adaxial and abaxial surfaces of the leaves. 'PBN 1626' showed significantly highest differential of aperture index and 'PBN 1444' showed significantly lowest High stomatal aperture index proved a suitable criterion for isolating heat-tolerant genotypes in wheat. Among the dates of sowing, 16 November showed significantly higher differential in aperture index, which was On a par with 16 December, whereas 16 October and 1 January showed the lowest.