Toward Understanding Genotype x Environment Interactions in Black Raspberry (Rubus occidentalis L.)

Over the last 75 years, the black raspberry industry in the United States has undergone a slow but steady contraction because of a lack of adapted, disease resistant cultivars. Recent research about the health benefits of a diet rich in polyphenolics, from black raspberries in particular, has led to a resurgence of interest in this fruit and a renewal of breeding efforts. This study seeks to advance and streamline identification of a variety of traits of interest to growers and consumers in black raspberry germplasm through phenotyping and socio-economic analyses. The information will be integrated into breeding programs with the goal of developing disease resistant cultivars that satisfy the demands of the marketplace, adding to the sustainability and profitability of the industry. Two related full-sib populations, designated ORUS 4304 (192 progeny) and ORUS 4305 (115 progeny), were planted across the production regions. Primocane (non-fruiting canes) vigor was rated from 1 (dead) to 9 (very vigorous) at each site. Initial analysis of genotype by environment (GxE) influences on primocane vigor indicated that overall the populations showed no significant difference in vigor in different environments; however, individual genotypes showed significant variation depending on site conditions. Vigor data will be compared with the genetic linkage map to determine which genomic regions contribute to the control of this complex trait. The genomic tools we are developing will be applied to the identification of quantitative trait loci (QTL) and alleles important for breeding objectives regionally and nationally.