CERTAIN STORAGE PROTEINS AND THEIR ROLE IN THE RESISTANCE OF SOME LEGUME SEED TYPES AND VARIETIES TO INFESTATION WITH THE COWPEA SEEDS BEETLE, Callosobruchus maculatus (F.)

Seventeen legume seed varieties belonging to ten types were analyzed for each of total proteins, trypsin inhibitors, vicilins and lectins to study the relationship between the presence of the storage seed proteins in legume seeds and resistance to infestation with the cowpea seeds beetle, Callosobruchus maculatus (F.) under no-choice bioassay at constant conditions of 29±1°C and 70 ± 5% RH. The tested types and varieties were cowpea (Fitriat, Forage and Kafr El-Sheikh),  fababean (Aquadams, Giza 843 and Sakha 1), pea (Master B and Smooth) common bean (Bronco and Nepraska), lupin (Giza 1 and White lupin), chickpea (Giza 195), soyabean (Giza 111), lentil (Giza 9), guar (Guvar bean) and lablab (Egyptian kidney bean). To clarify the impact of the storage seed proteins in legume seed varieties and types on infestation with C. maculatus, larval period, pupal period, least and mean complete developmental periods, number of emerged adults per female, percentage of adults emergence and sex ratio (as percentage of males) were determined. Moreover, susceptibility index, infested seeds (%), mean number of holes per infested seed, seeds weight loss (%), weight of early emerged adult and number of dead individuals inside seeds per female were assessed as infestation parameters. The obtained results showed that, each of total proteins, trypsin inhibitors, vicilins and lectins of different tested legume seed varieties and types are negatively correlated with all aforesaid resistance parameters with the exception of those respecting larval and pupal durations, least and mean complete developmental periods and number of dead individuals inside seeds per female. As regards total proteins of varieties, larval period, least and mean complete developmental periods, susceptibility index and number of dead individuals inside seeds per female reached high significance degree at 0.01 level of probability, whereas pupal period obviously showed significant correlation coefficient at 0.05 level of probability. But, the other studied resistance parameters did not demonstrate significant correlations. Significancy test of correlation relationships respecting trypsin inhibitors clearly proved to be insignificant for all studied characters, except for those of larval stage period, least and mean developmental periods which cleared highly significant correlations and significant ones with susceptibility index, number of holes per infested seed and number of dead individuals inside seeds per female. All tested seed varieties of guar, lupin and common bean revealed completely linear inverse relationship between trypsin inhibitors and susceptibility to cowpea seeds beetle infestation indicating deterring effects for insect development. Also, vicilins content proved that simple correlation coefficient values regarding the abovementioned resistance parameters reached high significancy degree excepting those concerning larval stage period, percentage of infested seeds, seeds weight loss percentage and weight of emerged adult that showed significant correlation as well as insignificant ones were recorded with sex ratio as percentage of adult males and number of dead individuals inside seeds per female. All tested legume seed varieties of soyabean- Giza111 and lentil- Giza 9 revealed almostly linear inverse relationship between vicilins and susceptibility to cowpea seeds beetle infestation and showed retarding effects for insect development. As concerns lectins of the infested legume seed varieties, the correlation relationships proved to be highly significant with larval stage period, least and mean complete developmental periods, susceptibility index and number of dead individuals inside seeds per female, while in case of number of emerged adults per female, adults emergence percentage, number of holes per infested seed and seeds weight loss percentage the correlation was significant. The correlation of other resistance parameters did not attain significancy degree.