Submitted to: Maize Genetics Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 14, 1996
Publication Date: N/A
Technical Abstract: Three resistance genes (wsm1, wsm2, and wsm3) to WSMV were identified in maize inbred Pa405 and mapped by RFLP analysis. To study the effects of these genes, NILs were developed by six generations of backcrossing followed by selfing using Pa405 as the donor parent and Oh28 as the recurrent parent. In the field, the resistance alleles Wsm1, Wsm2, and Wsm3 behaved as single dominants (1:1 resistant:susceptible segregation in backcross progenies when scored as seedlings) when plants were airbrush-inoculated with WSMV. Susceptible plants developed general mosaic (GM) symptoms. Wsm1 NIL plants remained symptomless, Wsm2 NIL plants developed a delayed limited mosaic (DL), and Wsm3 NIL plants developed a delayed dispersed spots and rings (DSR) symptom. However, different symptom responses were seen when NILs and their F(sub1)s with the recurrent parent were rub-inoculated with WSMV in the greenhouse. Wsm1/Wsm1, Wsm1/wsm1, and Wsm2/Wsm2 plants remained symptomless. Wsm2/wsm2 plants developed DL symptoms. Wsm3/Wsm3 plants developed DSR symptoms and Wsm3/wsm3 plants developed GM symptoms. Therefore, the level of stability and resistance of each of the three resistance genes differed between field and greenhouse conditions. These NILs will be used to study the mechanism of resistance to WSMV.