Genotypic Variation in Excised Leaf Culture Ability of Fodder Cowpea: A New Direction for Germplasm Evaluation

Abstract

Genotypic variability in rooting ability of excised leaves is of great importance in crop improvement programme. Rooting in excised leaves encourages leaf culture which in term helps in identification of stay green and disease resistant plants. In the present investigation we have tried to find the genotypic variation in senescence and root traits of excised forage cowpea leaves. Matured leaves were excised from 30 and 40 days old plants and immersed in water for 8-10 days. Roots were appeared in leaf petiole on 5th day of immersion. Observations were recorded on root length, number of roots, frequency of rooted leaves, chlorophyll content and senescence of excised leaves on 7th day. Results revealed significant variation in root length, root number, frequency of rooted leaves, chlorophyll contentand senescenceof detached leaves. The maximum root length was observed in case of UPC-2001 (8.26 cm) followed by Sweeta (7.18 cm).Length of the longest root ranged from 2.90 to 8.26 cm with a mean of 4.95 cm. Number of adventitious roots ranged from 7.8 to 36.67 with a mean of 19.46. Frequency of rooted leaf ranged from 0.10 to 1.00.The chlorophyll content in terms of SPAD units varied from 13.54 to 42.31.Senescence index ranged from 0.10 to 1.00.Three genotypes namely UPC-804, UPC-2001 and Sweetashowed the highest desirability index of 5.0. This investigation reveals variation in excised leaf culture ability  of forage cowpea genotypes. The excised leaf culture is the simplest, quickest and cheapest techniquethat could be used for identification of stay green and disease resistant fodder cowpea genotypes.