Evaluation of Vigna unguiculata var. Sesquipedadalis for yield, nutritional characteristics, and powdery mildew resistance
Cowpea and yard-long bean, mostly cultivated for green pod and seeds, are very important legume crops for protein and minerals, worldwide. For this project, fifty three yard-long bean genotypes were evaluated for yield attributes, powdery mildew (PM) disease resistance and nutritional content. Genotypes were planted at the Agricultural Research and Education Center (AREC), Tennessee in 2013; and the 32 better yielding genotypes from the 2013 field planting were replanted in 2014 in a randomized complete block design. For PM disease screening, 53 genotypes were planted in a greenhouse. Spores and hyphal fragments were collected from cowpea PM infected plants and internal transcribed spacer (ITS) sequencing was performed. For determination of proteins and minerals contents, inductively coupled plasma mass spectrometry (ICP-MS) was done on 31 yard-long bean genotypes. Combined analysis by year showed, 7 genotypes had higher seed yielder/hectare (>1.5 tons/ha). Total of 11 genotypes had longest pod length (>40 cm). Pod length was negatively correlated with 10 pod weight, 10 pod seed weight, seed yield/hectare and 10 pod seed number; but correlations other than that were positive. Pod seed weight was positively and strongly correlated to pod weight (r =0.93) and with pod seed number (r = 0.90). One genotype (PI 352957 03 SD) was PM resistant, two were moderately resistant (PI 418979 03 SD) and PI 478396 01 SD) and other genotypes were susceptible. Disease began to develop on the 14th day and increased to a maximum level by the 23rd and 37th days. Afterward, the disease began to decrease to 62nd day and onward. In Tennessee, cowpea PM is caused by Erysiphe polygon. This is the first report of this pathogen in Tennessee. Protein, calcium, magnesium, potassium, manganese, phosphorus, copper, zinc, iron, Sulphur and boron content, were differed in yard-long bean genotypes; and were 20.70%, 0.38%, 0.33%, 1.82%, 54.37%, 0.47%, 13.47 ppm, 60.69 ppm, 382.39 ppm, 0.22 % and 23.30 ppm, respectively^
Devendra Prasad Bhandari,
"Evaluation of Vigna unguiculata var. Sesquipedadalis for yield, nutritional characteristics, and powdery mildew resistance"
ETD Collection for Tennessee State University.