Host plant accessions determine bottom-up effect of snapmelon (Cucumis melo var. momordica) against melon fly (Bactrocera cucurbitae (Coquillett))

The melon fly, Bactrocera cucurbitae (Tephritidae: Diptera) is an important pest of snapmelon (Cucumis melo var. momordica), leading to significant losses in yield in the hot arid agro-climate of India. The accessions IC- 430190 (11.21%), DKS-AHS 2011/4 (14.97%) and DKS-AHS 2011/3 (18.57%) were found to be novel resistant accessions against melon fly, B. cucurbitae infestation. Free amino acid and total soluble solid (TSS) were in positive correlation with percent fruit infestation whereas phenols, tannin, total alkaloids and flavonoid contents had significant negative correlation with percent fruit infestation. The percent fruit infestation had significant positive correlation with fruit length, fruit diameter and flesh thickness and negative correlation with length of ovary pubescence, rind hardness at immature stage, rind hardness at mature stage and pericarp thickness. Based on Kaiser Normalization method, two principal components (PCs) were extracted explaining cumulative variation of 82.80% in melon fly infestation. PC1 explained 53.41% of the variation while PC2 explained 29.39% of variation. The flavonoid, total alkaloid, tannins, phenols content, length of ovary pubescence and rind hardness were the novel antibiosis and antixenotic characters found in snapmelon resistant melon fly, B. cucurbitae and therefore, could be used as marker traits in plant breeding programs to select resistant accessions.