Priti Saxena* and James Weeks
The goal of developing high-performing cultivars for organic production, driven by the declining performance of conventional germplasm in organic agriculture, is a crucial factor in closing the yield gap between conventional and organic farming. The on-going research at Cal Poly Pomona's Certified Organic Spadra Farm in Southern California, evaluated 72 F2 breeding lines of fresh market slicers, grape, cherry, and plum tomatoes in 2019. Ten superior lines with higher yield, and fruit quality were selected to advance into a replicated trail in 2020. We predicted a positive response to selection for the desired traits in this environment. Data were collected on fruit quality traits including scaring, and shape, growth habit, and yield, for both years, and dissolved soluble solids (BRIX) were collected in 2020. Analysis included ANOVA, multiple comparison testing, broad-sense heritability, correlations between traits, and response to selection. The significant (p<0.05) differences between the 2019 and 2020 seasons were found for all traits. However, response to selection showed that yield had responded negatively to selection indicating a possible influence of environmental factors while broad-sense heritability for yield was estimated at 0.22, suggesting remaining potential to select on yield. The fruit quality traits showed positive response to selection and highest broad-sense heritability estimated at 0.91 for stem scaring. Broad-sense heritability for BRIX was estimated at 0.67 and correlated to yield at R = 0.22 p<0.0001 for 2020 tomato breeding lines. Six of the best performing lines in 2020 were selected for advancement in the organic breeding program at Cal Poly Pomona for cultivar development.?
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