Estimation of yield losses in broad bean due to Meloidogyne arenaria in Egypt

Loss in yield of broad bean grown in sandy soil naturally infested with root-knot nematode Meloidogyne arenaria was estimated during two successive seasons. Severity of nematode infestation (damage) was assayed at harvest stage as root-gall indices (GI) based on scale of 1-6 (1= no infection and 6= 100% root galling). In the first season (2014-2015) relationship between nematode damage and yield of broad bean was negative, however no significant reduction in growth and yield (p= 0.05) was obtained at all nematode root gall indices. Correlation coefficient between nematode damage and yield was low, 0.38 in case of pod yield and 0.40 in case of dry seeds. In second season (2015-2016), both pods and dry seeds yield were significantly reduced by 10.6% and 15.2%, respectively at severe infestation (GI=6). Also correlation coefficient between nematode and yield was 0.92 in case of nematodepod yield and 0.91 in case of nematode-seed yield. Seed contents viz., proteins, carbohydrates, zinc and copper decreased at severe infestation in the second season, while in the first season quality of seeds was not affected.