Genetic and chemical analyses of six cowpea and two Phaseolus bean species differing in resistance to weevil pest

Abstract

The objective of this work was to evaluate the genetic variability among six cowpea (Vigna unguiculata) cultivars differing in their resistance to Callosobruchus maculatus (F.) weevil. Two resistant bean cultivars were used to compare between the sensitive, moderate tolerant, and high tolerant cowpea cultivars. The differentiations were performed by using random amplified polymorphic DNA (RAPD) fingerprinting, protein concentration and organic and non-organic components in seed coat. Six polymorphic primers were identified, resulting in different informative bands. Based on polymorphic profiles, three clusters were formed. Clustering was mainly affected by the resistance to weevil pest. The sensitive cowpea cultivars were separated in one group, the moderate tolerant and high tolerant cultivars came in separate groups, and finally, the resistant bean cultivars separated clearly in one distinct group. The most interesting result was represented by concentration of total protein in the seed coat. The protein concentration in the resistant bean cultivars were approximately 50% less than concentration in each of the moderate tolerant and sensitive cultivars of cowpea. Ferric ions were about 25% less than the moderate tolerant and sensitive cultivars. The concentrations of calcium and potassium in seed coats were higher in the resistant beans than in cowpea cultivars. Cobalt was about four times higher in resistant bean than in the sensitive and moderate tolerant cowpea cultivars, which may play a major role in seed resistance to weevil.

GENETIC RELATIONSHIPS AMONG SOME MAIZE (Zea mays L.) GENOTYPES ON THE BASIS OF GENE ACTION AND RAPD MARKERS UNDER DROUGHT STRESS

“…Similar results obtained by Heun and Helentjaris (1993); Lanza et al (1997); Moeller and Schall (1999) and Valdemar et el. (2004), and in other species obtained by Tanttawi et al (2007) in faba bean and Abdel-Sabour et al (2010) in cowpea and phaseolus RAPD experiments. This result of polymorphic bands was smaller than (89%) obtained by Okumus (2007).…”

Pest Control in Organic Systems

“…The reaction of cultivars resistant to pests and the nematode default may be determined by its presence in the plant silica [22], iron [23] genes that provide resistance [18,24,25], or protein presence in bean or cowpea [23,26,27].…”

Seed coat phytochemistry of both resistant and susceptible seeds affords some protection against the granivorous beetle Callosobruchus maculatus

“…By contrast, they did find high levels of vicilin in the seed coat of P. vulgaris, suggesting that this protein affords protection against herbivory by 3 C. maculatus. However, the phytochemistry of the seed coat of P. vulgaris and V. unguicuata differ in several other respects (Abdel-Sabour et al 2010), rendering it difficult to pinpoint the exact mechanism of phytochemical defense without bioassays of different seed coat fractions.…”