Anatomical Breeding for Altered Leaf Parameters in Tomato Genotypes Imparting Drought Resistance Using Leaf Strength Index

摘要

Present investigation was carried out with aim to understand role of leaf anatomy in drought resistance. Seventeen tomato genotypes were screened for petiole, leaf anatomy and stomatal features to understand the secret of drought resistance. Total petiole thickness, compact parenchyma and more width of phloem vessels, more number of xylem vessels were important characters of resistant genotypes. Leaves of resistant type had longer palisade mesophyll cells with compact arrangement, thin spongy mesophyll layer leading to higher tissue ratio (Palisade mesophyll: Spongy mesophyll). Thickness of leaves was invariably more in drought resistant genotypes (500-550 urn) as compared to susceptible ones (400-450 urn). Remarkably reduced number of stomata, bigger size and more distance between them was highlighting character of drought resistant genotypes as compared to abundant, smaller size and closely spaced stomata in susceptible genotypes. We introduce here a new parameter "Leaf Strength Index" which is simple to study and cost effective. This can be potential method for screening large number of genotypes for categorizing them in relation to their ability of drought resistance. These findings will be a new light towards breeding drought resistant genotypes giving emphasis on anatomical features.