Submitted to: Journal of American Pomological Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/15/2013
Publication Date: 7/22/2013
Citation: Ledbetter, C.A., Mercure, E., Halasz, J., Hegedus, A. 2013. Yield, pollination aspects and kernel qualities of almond (Prunus amygdalus Batsch) selections trialed in the Southern San Joaquin Valley. Journal of American Pomological Society. 67(3):126-136. Interpretive Summary: Publically sponsored trials are often initiated to demonstrate strengths and weaknesses of newly developed varieties compared to commonly used cultivars. Newly developed almond varieties are evaluated in this manner, but almond variety trials are initiated very infrequently because of orchard longevity. Due to a current need for yield and quality evaluations of advanced almond selections, collaboration between ARS and private industry led to initiation of an almond variety trial to examine kernel yield and product quality in the Southern San Joaquin Valley. Almond kernel yield was quantified over three harvest seasons for nine almond selections and the commonly used Nonpareil cultivar. Further, almond selections were evaluated for kernel quality characters and harvest defects. Five of the nine selections were removed from the trial after the third harvest due to unacceptably low kernel yields or specific harvest defects. One of the remaining selections demonstrated a cumulative yield that is significantly higher than that of Nonpareil. By initiating and reporting on this variety trial in a time period between publically sponsored trials, yield potential of new almond selections is being provided to almond producers in a timelier manner.
Technical Abstract: A field trial was established in the Southern San Joaquin Valley to determine yield potential for nine almond selections grown under commercial conditions. Kernel yields were first quantified in 2008, at the end of the third growing season, and continued through the 2010 harvest. Harvested tonnage varied significantly, depending on the particular selection, specific field location and harvest year. The almond selections were genotyped for S-locus alleles, characterized phenologically during bloom, and analyzed for differences in kernel dimensions, pellicle color profiles, nut defects and harvest quality parameters. Bloom duration and overlap of the nine experimental selections generally coincided with that of Nonpareil during the three examined bloom periods. Analysis of S-alleles revealed semi- or cross-incompatible pairs with some commercial cultivars, and confirmed the self-compatibility status of four of the trialed selections. The effect of harvest year was significant on all examined kernel shape and appearance characters as well as all nut defects and harvest quality parameters except for the level of blank and shriveled kernels. Cumulative kernel yield differences and specific character faults have led to the removal of five selections from the trial after three harvest seasons.