Screening of alfalfa cultivars to the lesion nematode Pratylenchus penetrans for commercial release.

In three separate experiments in a glasshouse 37 alfalfa cultivars were evaluated for their tolerance to the lesion nematode Pratylenchus penetrans compared with the susceptible cultivar 'Baker'. Dry weight and fresh weight of foliar and root system along with soil, root and total nematode population were considered for tolerance level of alfalfa. In the first (13 cultivars) and second (11 cultivars) experiment total and root population of all the tested cultivars were significantly lower as compared to the susceptible cv Baker. In two cultivars, ZN 9541 and ZN 9651 a significant reduction in root and total nematode population were observed with an increase in shoot dry weight. In two cultivars, ZM 9421 and ZB 9546, fresh shoot weight significantly increased as compared to the susceptible cultivars. In the third experiment among the 13 cultivars tested, a significant reduction in nematode population with an increase in fresh and dry weight of root along with fresh shoot weight was observed in ZC 9751A. However, in two cultivars although there was no significant change in nematode population, fresh shoot weight and dry root weight increased.