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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #313280
Title: Diallel crossing among doubled haploids of cucumber reveals significant reciprocal-cross differences

Author
item SHEN, JIA - University Of Wisconsin
item DIRKS, ROB - Rijk Zwaan Breeding Bv
item Havey, Michael

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2015
Publication Date: 4/12/2015
Publication URL: https://handle.nal.usda.gov/10113/60778
Citation: Shen, J., Dirks, R., Havey, M.J. 2015. Diallel crossing among doubled haploids of cucumber reveals significant reciprocal-cross differences. Journal of the American Society for Horticultural Science. 140(2):178-182.

Interpretive Summary: Cucumber is an excellent plant for studying cytoplasmic effects on performance because chloroplasts show maternal and mitochondria paternal transmission. We produced doubled haploids (DH) from divergent cucumber populations, generated reciprocal crosses in a complete mating scheme, measured fresh and dry weights of plants 22 to 30 days after planting, estimated combining abilities and heterosis for early plant growth, and assessed performance differences between reciprocal hybrids with identical nuclear genotypes. Across experiments, general (GCA) and specific (SCA) combining abilities and reciprocal effects, as well as their interactions with replicated experiments, were all highly significant. Hybrids consistently out-performed parental lines with average heterosis over mid-parent values between 14% and 30%. Significant reciprocal effects were detected. A mitochondrial mutant showed negative effects when used as the male due to paternal transmission of mitochondria, but not as the female parent. Reciprocal hybrids were identified that differed significantly for dry and fresh weights across experiments, indicating that cucumber breeders should consider the direction of crosses when producing hybrid cultivars. The significantly different performances of reciprocal hybrids from crossing among DH parental lines offer a unique opportunity to study gene-expression differences associated with chloroplast versus mitochondrial effects in identical nuclear backgrounds, and should provide insights about specific nuclear genes or pathways that interact with the organelles to enhance plant performance. This research will be of interested to plant breeders across crops because of the importance of the cytoplasm in overall plant performance.

Technical Abstract: Cucumber is an excellent plant for studying organellar effects on phenotypes because chloroplasts show maternal and mitochondria paternal transmission. We produced doubled haploids (DH) from divergent cucumber populations, generated reciprocal crosses in a diallel mating scheme, measured fresh and dry weights of plants 22 to 30 days after planting, estimated combining abilities and heterosis for early plant growth, and assessed performance differences between reciprocal hybrids with identical nuclear genotypes. Across experiments, general (GCA) and specific (SCA) combining abilities and reciprocal effects, as well as their interactions with replicated experiments, were all highly significant (P<0.001). Hybrids consistently out-performed parental lines with average heterosis over mid-parent values between 14% and 30%. Significant reciprocal effects were detected. As expected a mitochondrial mutant (MSC3) showed negative effects when used as the male due to paternal transmission of mitochondria, but not as the female parent. Reciprocal hybrids were identified that differed significantly (P=0.032 to 0.001) for dry and fresh weights across experiments, indicating that cucumber breeders should consider the direction of crosses when producing hybrid cultivars. The significantly different performances of reciprocal hybrids from crossing among DH parental lines offer a unique opportunity to study gene-expression differences associated with chloroplast versus mitochondrial effects in identical nuclear backgrounds, and should provide insights about specific nuclear genes or pathways that interact with the organelles to enhance plant performance.