ANTIBIOSIS EFFECTS OF OKRA AND THEIR HYBRID DERIVATIVES ON SHOOT AND FRUIT BORER

nvestigation was carried out to study the antibiosis mechanisms of resistance in okra accessions and their hybrid derivatives against Shoot and Fruit borer Earia vittella and the role of various biophysical factors of resistance. On estimating the antibiosis effects of the test accessions on the various life stages of E. vittella, the lowest total larval duration (14.62 days) was recorded on Hy2. The accessions Hy1 and Hy2 recorded the shortest larvae of the final instar (1.0 cm) and the longest was (1.8 cm) in the accession Arka Anamika. Regarding mean larval weight, the larvae reared on Arka Anamika gained maximum of 0.680 mg where as accession Hyl gained the lowest weight of 0.315 mg. Highest larval mortality was recorded on the accession Hy2 followed by Hy1. Regarding the pupal characters, highest pupal weight (0.916mg) and maximum length of pupa recorded on the accession Arka Anamika whereas the accession Hy2 recorded the least pupal weight of 0.326 mg. The accession Hy2 recorded maximum total pupal duration (13.2 days). Cent percent adult emergence was recorded in the accession Arka Anamika. There was no adult emergence recoded in the accession Hy2. The highest adult longevity period of both male and female recorded on the accession Arka Anamika. Mean egg period and mean hatchability also high on the accession Arka Anamika followed by Hy6. Among the biopysical factors, maximum number of trichomes and high length and breadth of trichomes were recorded on the accession Hy2. Fruit length of Arka Anamika was greater than other accessions. Fruit width of Salem Local was greater than other accessions. Fruit angle to stem / branch of accession Hy4 was higher than other accessions. A significant negative correlation was observed among trichome density, trichome length, fruit width and fruit angle to stem with larval mortality, pupation percentage and adult longevity. Keywords: Okra accessions, Hybrid derivatives, Antibiosis and Biophysical factors