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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #231281
Title: Detection of vegetative bud dormancy QTL in peach

Author
item CHAPARRO, J - UFL, GAINESVILLE
item Beckman, Thomas

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2008
Publication Date: 7/10/2008
Citation: Chaparro, J.X., Beckman, T.G. 2008. Detection of vegetative bud dormancy QTL in peach [abstract]. HortScience. 43(4):1269.

Interpretive Summary: Most temperate tree species cease growth during the winter and enter a state of endodormancy that requires the exposure of vegetative and floral buds to cold temperatures (below 7°C) to initiate normal growth in the spring. The length of the cold treatment required for the resumption of growth is defined as the chilling requirement. Variation in chilling requirement is the primary factor determining the range of adaptation of peach (Prunus persica (L.) Batsch) cultivars in the eastern US. Chilling requirement in peach varies quite extensively ranging from approximately 50 hrs for subtropical cultivars like Red Ceylon to an excess of 1000 hrs for temperate zone cultivars like Late Arkansas. Low chill peach cultivars growing in high chill areas are at the risk of breaking dormancy during transient warm periods and the resulting tender flower and vegetative tissues are damaged by freezing temperatures. Conversely, in low chill regions, cultivars with high chilling requirements will not receive sufficient chill hours to allow for normal vegetative and flower bud break. Mature F2 seed was collected from a set of 4 F1 hybrids originating from a 'Late Arkansas' x 'Flordaguard' (200 hrs.) cross. The four F1 hybrids were screened with markers from the Prunus reference genome map and the F1 with the highest heterozygosity was selected for genetic analysis. The selected F2 population consists of approximately 350 genotypes planted in Gainesville, FL and vegetative bud break data was collected during spring 2007. Phenotypic segregation for vegetative budbreak ranged from less than 150 hrs. to in excess of 450 hrs. Analysis of the 2007 vegetative budbreak data detected three QTL located in linkage groups 1, 4 and 7 of the Prunus reference map.

Technical Abstract: Most temperate tree species cease growth during the winter and enter a state of endodormancy that requires the exposure of vegetative and floral buds to cold temperatures (below 7°C) to initiate normal growth in the spring. The length of the cold treatment required for the resumption of growth is defined as the chilling requirement. Variation in chilling requirement is the primary factor determining the range of adaptation of peach (Prunus persica (L.) Batsch) cultivars in the eastern US. Chilling requirement in peach varies quite extensively ranging from approximately 50 hrs for subtropical cultivars like Red Ceylon to an excess of 1000 hrs for temperate zone cultivars like Late Arkansas. Low chill peach cultivars growing in high chill areas are at the risk of breaking dormancy during transient warm periods and the resulting tender flower and vegetative tissues are damaged by freezing temperatures. Conversely, in low chill regions, cultivars with high chilling requirements will not receive sufficient chill hours to allow for normal vegetative and flower bud break. Mature F2 seed was collected from a set of 4 F1 hybrids originating from a 'Late Arkansas' x 'Flordaguard' (200 hrs.) cross. The four F1 hybrids were screened with markers from the Prunus reference genome map and the F1 with the highest heterozygosity was selected for genetic analysis. The selected F2 population consists of approximately 350 genotypes planted in Gainesville, FL and vegetative bud break data was collected during spring 2007. Phenotypic segregation for vegetative budbreak ranged from less than 150 hrs. to in excess of 450 hrs. Analysis of the 2007 vegetative budbreak data detected three QTL located in linkage groups 1, 4 and 7 of the Prunus reference map.