Abstract
The genetic basis and mechanism for resistance to root-knot nematode was determined in six BCSF2 peanut breeding lines. The donor parent for resistance to root-knot nematode in all breeding lines was TxAG-7 and the recurrent parent used was Florunner in all breeding lines, except TP268-3 for which NC7 was the recurrent parent. Resistance of TxAG-7 was derived from the wild species, Arachis batizocci, A. ca-rdenasii, and A. diogoi. Resistance was defined as an inhibition of nematode reproduction relative to that of the susceptible recurrent parent. The ratio of resistant to susceptible individuals in all six BCSF2 lines was not different (P < 0.05)from that predicted for a single dominant gene. However, segregation ratios for three lines were also consistent with two dominant genes, both heterozygous. To determine the resistance mechanism in the BC5F2 breeding lines, resistant individuals from two BC5F2 peanut breeding lines were vegetatively propagated and used to determine the effect of resistance genes on nematode development. The rate of nematode development in resistant individuals was significantly reduced from that in Florunner. There was definite evidence for hypersensitive response in resistant individuals. The observed difference in nematode development was consistent with the poor development of feeding sites in resistant individuals. Thus, the reduced development of nematode in resistant individuals may be caused by the insufficient uptake of nutrient from poorly developed feedin sites.
Choi, Kuicheon (1997). Genetics and mechanism of resistance to Meloidogyne arenaria in advanced generation peanut germplasm. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1997 -THESIS -C462.