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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #255846
Title: A single recessive gene conferring short leaves in romaine x Latin type lettuce (Lactuca sativa L.) crosses, and its effect on plant morphology and resistance to lettuce drop caused by Sclerotinia minor Jagger.

Author
item Hayes, Ryan
item WU, BO MING - Oregon State University
item SUBBARAO, KRISHNA - University Of California

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2010
Publication Date: 6/1/2011
Citation: Hayes, R.J., Wu, B., Subbarao, K.V. 2011. A single recessive gene conferring short leaves in romaine x Latin type lettuce (Lactuca sativa L.) crosses, and its effect on plant morphology and resistance to lettuce drop caused by Sclerotinia minor Jagger. Plant Breeding. 130:388-393.

Interpretive Summary: Understanding the relationship between plant morphology and disease resistance is crucial to successful breeding, particularly resistance to lettuce drop caused by Sclerotinia minor. Latin type lettuce cultivars are small plants with upright leaves longer than they are wide, similar to romaine type cultivars but considerably shorter. The objective of this research was to determine the number and effects of genes controlling plant height in romaine x Latin crosses and characterize the effect on lettuce drop resistance. Short stature was conditioned by a single recessive gene in F1, F2 and F3 families from nine romaine x Latin crosses tested in 2007, 2008, and 2009 field experiments. The gene, named short leaf 1 (sl1), affects only leaf length in rosette plants and is morphologically distinct from other known dwarfing genes. In two S. minor infested field experiments with 75 F3 romaine x Eruption families, no difference in disease resistance was detected between short (sl1, sl1), tall (Sl1, Sl1) or segregating families. Therefore, development of romaine cultivars from crosses with ‘Eruption’ is feasible.

Technical Abstract: Understanding the relationship between plant morphology and disease resistance is crucial to successful breeding, particularly resistance to lettuce drop caused by Sclerotinia minor. Latin type lettuce cultivars are small plants with upright leaves longer than they are wide, similar to romaine type cultivars but considerably shorter. The objective of this research was to determine the segregation for plant height in romaine x Latin crosses and characterize the effect of height on lettuce drop resistance derived from the Latin cultivar Eruption. The frequency of short plants was conditioned by a single recessive gene in F1, F2 and F3 families from nine romaine x Latin crosses tested in 2007, 2008, and 2009 field experiments. The gene, named short leaf 1 (sl1), affects only leaf length in rosette plants and is morphologically distinct from other dwarfing genes. In two S. minor infested field experiments with 75 F3 romaine x Eruption families, no difference in disease incidence was detected between short (sl1, sl1), tall (Sl1, Sl1) or segregating families. Therefore, development of romaine cultivars from crosses with ‘Eruption’ is feasible.