Submitted to: Journal of Genetics and Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 2001
Publication Date: January 31, 2001
Citation: Ledbetter, C.A., Palmquist, D.E. Evaluation of advanced almond (Prunus amygdalus Batsch) selections relative to the commercial almond cultivars Mission, Nonpareil and Padre. I. Bloom characteristics. Journal of Genetics and Breeding. 2002. v. 56. p. 43-49.
Interpretive Summary: California's 1.1 billion dollar almond industry is dependent upon bees to cross-pollenize the 450,000+ acres of trees each year. Climatic factors can cause problems with bees and affect the annual yield of almonds. The use of specific almond varieties to optimize cross-pollenization can benefit in boosting annual nut yield. Almond selections from a breeding program have been evaluated for their specific capacity to match bloom periods and become effective pollenizers for important almond varieties. Several almond selections were identified that effectively pollenize the important Nonpareil variety. The development and utilization of new and efficient pollenizers for Nonpareil will ensure that yield will not be limited by problems during the bloom period.
A collection of almond selections from an almond breeding program and several reference cultivars were evaluated for bloom characteristics during a four year period. Ten percent, fifty percent and full bloom dates, as well as date of petal fall, and the interval of bloom were scored for each of 27 almond accessions. K-means clustering analysis demonstrated the relative importance of each specific variable, and divided the almond collection and reference cultivars Mission, Nonpareil and Padre into four clusters. Multivariate analysis of variance (MANOVA) for the five bloom characteristic variables reinforced the K-means analysis showing that the almond collection should be divided into the four specific clusters based on data collected during the four years of bloom. While F-ratios for bloom intervals were non-significant during two of the four years of the study, all other evaluated variables during each of the four years were highly significant (p<0.01) in the division of the almond collection into the fou clusters. While specific membership in the four bloom clusters varied between years, four of the 24 ARS almond accessions were included in the same bloom cluster as Nonpareil in three of the four years of the study.