GENOTYPIC AND SEASONAL VARIATIONS IN TRICHOME DENSITY IN TENDER SHOOT OF MULBERRY (MORUS SPP.)

摘要

The relationship of trichome density with antixenosis and drought tolerance have been reported in many crop plants. The trichome density (the number per mm length of epidermis) in transverse sections of stem, petiole, lamina-adaxial and lamina-abaxialsurfaces in tender shoots of eight popular mulberry genotypes, in summer, rainy and winter seasons was studied. All the genotypes showed significant differences in trichome density, in respect of both glandular and non-glandular trichomes in all parts of the shoot in all seasons. Trichomes were comparatively more dense in stems, moderately dense in both petiole and abaxial lamina, but sparse in adaxial lamina. Non-glandular trichomes were more in stems, petioles and abaxial laminae, and glandular trichomes were more in adaxial laminae. Mysore local and RFS_175 genotypes recorded high trichome density in all parts of the shoot, which may be correlated with their reported resistance to pests and tolerance to drought. Among other genotypes, M, and MI- i02 showed sparse trichomes while DD, V_1Ber. S_1 and Ber.C_776 exhibited moderate trichome density. Trichome density was high in summer, moderate in winter and low in rainy season. The information on trichome density of different genotypes is highly useful to mulberry breeders.