Biochemical Evaluation of Forage Pea Genotypes with a View to Breeding for Resistance to Pea Weevil Bruchus pisi L.
A. ILIEVA and B. DOCHKOVA
Forage Research Institute, BG -5800 Pleven, Bulgaria
ILIEVA, A. and B. DOCHKOVA, 2000. Biochemical evaluation of forage pea genotypes with a view to breeding for resistance to pea weevil Bruchus pisi L. Bulg. J. Agric. Sci., 6: 169-174
Studies were conducted during the 1996-1998 period. A competition variety trial on wintering forage pea with 10 varieties and lines from Bulgaria and a competition variety trial on spring forage pea with 3 varieties from France, 4 varieties and lines from Bulgaria were carried out in the experimental field of the Forage Research Institute – Pleven. The degree of the grains damaged by Bruchus pisi L. was determined two months after pea harvesting and conclusion of larva development. Dried and ground samples were used for chemical analyses. It was found that for the spring forage pea the pod and grain coat and interior contain no condensed tannins. The degree of the grains damaged by Bruchus pisi L. is high and for some varieties in reaches 46.7%. For the wintering forage pea condensed tannins are only contained in the grain coat. There is a negative correlation ( r = -0.94) between their content and the degree of attack by Bruchus pisi L. Of interest for the breeding are the lines Uzbekskii 71 x Lyutzkanovich and No 136 x Pleven 4 for which the grain coat contains most tannins (2.15 and 2.13%) and the degree of damaged grains is relatively low (19.1 and 18.1%).The grain coat of the wintering forage pea varies in coloration. Compared to marbled grains the non-marbled ones contain 1.3 times more condensed tannins and are attacked 1.5 times less by Bruchus pisi L. The coloration and the condensed tannin content in the grain coat can serve as characteristics for selection of genotypes tolerant to Bruchus pisi L. The wintering and spring forage pea don't differ in total phenol content in the grain. Cyanglycosides are not contained in the pod and grain of forage pea. These two biochemical characteristics cannot serve for evaluation of resistance to Bruchus pisi L.
Key words: forage pea, pea weevil, condensed tannins