Evaluation and Genetic Analysis of Five Parental Varieties Resistant to Rice Blast Pathogen in Heilongjiang Province

Five F2 segregation populations, derived from crosses between the susceptible japonica cultivars （cvs.） Kongyul31 and donor cvs. Aichi Asahi （AA）, BL1, Digu, Pai-kan-tao （PKT） and Oryzica Llanos 5 （ORL5）, were used to evaluate their natural resistance to blast in cold region. The field test of their blast resistance was conducted in 858 Farm, which showed that Aichi Asahi, BL 1 and Digu were highly resistant to either leaf blast or neck blast and could be used to develop molecular breeding by design, and genetic analysis indicated that the field resistance of Aichi Asahi, BLland Digu to leaf blast and neck blast was controlled by a single dominant gene, and the leaf blast and neck blast resistance in the donor cv. Pai-kan-tao was inherited as a single recessive gene, the neck blast resistance of the donor cv. Oryzica Llanos 5 was controlled by a single recessive gene while its leaf blast resistance was not controlled by this gene. These results suggested that five parental varieties positively contributed to resistance to either leaf blast or neck blast and could be used to expand the genetic germplasms resistant to blast in cold region using molecular assisted selection.

Inheritance of Perpetual Blooming in Rosa chinensis ‘Old Blush'

Perpetual blooming is one of the most important biological and economical traits in modern rose, while the genetic basis underlining the control of this trait is poorly investigated. With an aim in dissecting the genetic determinism of perpetual blooming, we developed six rose populations(OB, W, F1, F2, BC1 OB and BC1W) derived from a WOB population [interspecific diploid hybridization between Rosa chinensis ‘Old Blush'(OB) and R. wichuriana ‘Basye's Thornless'(W)]. Perpetual blooming is absent both in a F1 population with 296 individuals and a BC1 W population(W as the backcross parent) with 150 individuals. However, the perpetual blooming trait showed a typical 3︰1 segregation in a backcross population BC1 OB with OB as the backcross parent. In this population with 300 individuals, 83 plants had the perpetual blooming phenotype while the other 217 featured non-perpetual blooming, indicating that the perpetual blooming trait is very likely controlled by two recessive genes in R. chinensis(rpb1 and rpb2). These genetic data suggest that the inheritance of rose perpetual blooming may be controlled by a complex mechanism.