Field Assessment of Outcrossing from Transgenic Pea (Pisum Sativum L.) Plants
The frequency of outcrossing from a transgenic line of peas into three cultivars ('Carneval', 'Montana', 'Tipu') was studied in the field in 1997 and 1999. Two dominant traits, normal leaf form and a highly-expressed β-glucuronidase (gusA) gene, were used as markers of pollen transfer. Because of heterogeneity in the commercial seed sources, leaf form alone was unreliable for assessing pollen migration into 'trap' plants. Of approximately 9000 offspring tested, only five plants scored positive for the presence of both markers. All five were located in 'trap' plots situated near the transgenic line. This represents a mean outcrossing rate of 0.07%.
Stigma Receptivity in Peas (Pisum sativum L.1)
AVAILABLE information on stigma receptivity in peas -t"V (Pisum sativum L.) and its relation to seed set is meager. Wellensiek (7) suggested pollinating peas at the time they are emasculated and again 2 days afterwards to insure seed set. Bond (2) wrote that the peak of receptivity occurred at the time flowers were fully opened. However, there appears to have been no extensive research on this subject. Experiments were performed in 1951 and 1952 to determine (1) at what stage pea stigmas were most receptive, (2) the duration of receptivity, and (3) the exact location of the stigmatic surface. The results of these investigations will be reported here.
Linkage mapping of sbm-1, a gene conferring resistance to pea seed-borne mosaic virus, using molecular markers in Pisum sativum
SummaryThe location of sbm-1 on the Pisum sativum genetic map was determined by linkage analysis with eight syntenic molecular markers. Analysis of the progeny of two crosses confirmed that sbm-1 is on chromosome 6 and permitted a more detailed map of this chromosome to be constructed. The inclusion of Fed-1 and Prx-3 among the markers facilitated the comparison of our map with the classical genetic map of pea. The sbm-1 gene is most closely linked to RFLP marker GS185, being separated by a distance of about 8 cM. To determine the practical value of GS185 as a marker for sbm-1 in plant breeding programs, the GS185 hybridization pattern and virus-resistance phenotype were compared in of a collection of breeding lines and cultivars. Three GS185 hybridization patterns were discerned among the lines. A strong association was found between one of these patterns and resistance to PSbMV.