Location: Crop Improvement and Protection ResearchTitle: Genetics of extended storage life
|Sthapit Kandel, Jinita|
|PENG, H - University Of California|
|TRUCO, M - University Of California|
|MICHELMORE, R - University Of California|
Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: 2/14/2020
Publication Date: 3/16/2020
Citation: Simko, I., Sthapit Kandel, J., Peng, H., Hayes, R.J., Truco, M.J., Michelmore, R.W. 2020. Genetics of extended storage life. Future of Lettuce Conference, March 16, 2020, Pismo Beach, California.
Technical Abstract: Fresh-cut lettuce (Lactuca sativa L.) packaged as salad mixes is a highly perishable product and cultivars bred with extended shelf life could reduce waste. Understanding the inheritance of shelf life is needed to develop efficient breeding schemes. We investigated the genetics of deterioration on two recombined inbred line (RILs) populations consisting of 95 and 78 RILs, seven F2 families (with 50 plants per family) developed by crossing cultivars with rapid and slow rate of deterioration, and a set of 493 accessions used for genome-wide association study (GWAS). Plants were grown in major lettuce producing areas of Salinas Valley, California and Yuma, Arizona, planted at several planting dates, and handled with or without vacuum cooling on the harvest day. Salad was processed similarly as in commercial production, packaged in modified atmosphere packaged (MAP) bags, stored in the dark at 4 °C, and evaluated for the rate of deterioration. The earliest signs of deterioration occurred within a week after processing in rapidly deteriorating genotypes, while in slow deteriorating genotypes symptoms were not apparent until three weeks after processing. The major genetic determinant of deterioration in all populations was the quantitative trait locus (QTL), qSL4, located on linkage group (LG) 4. This QTL was detected in every experiment, regardless of the tested population, location, planting date, or processing method. Three additional minor effect QTLs were detected on LGs 1, 4, and 5 in some of the experiments. qSL4 explained 40 – 90% of the total phenotypic variation in bi-parental mapping populations and F2 families, and 24% in the GWAS population. Intermediate rate of deterioration was found in individuals having heterozygous alleles at qSL4, indicating an additive effect of the alleles. An assay based on single nucleotide polymorphism (SNP) was developed to accurately identify genotypes with different deterioration rates of fresh-cut lettuce. Cloning of this gene will allow a detailed study of the deterioration process in fresh-cut lettuce.