CHARACTERIZATION OF OUTSTANDING GUAVA GERMPLASM FROM THE CALVILLO-CAÑONES REGION, MÉXICO

Abstract

Twelve guava (Psidium guava L.) selections were phenotypically and genetically characterized in 12 years-old plants growing at Huanusco, Zacatecas, México. Ten fruit characteristics, fruit growth kinetics, phenology and fruit productivity were evaluated. Selections were analyzed using Random Amplified Polymorphic DNA (RAPD's). Equatorial diameter, mesocarp thickness, seed weight, mesocarp color and fruit shape were the best descriptive fruit characteristics. A negative relationship was found between total soluble solids content and fruit size. Guava fruit growth showed a trimodal or doublesigmod growth pattern, that consisted on three phases having different growth rates. Selection 106 was different from all other selections, and showed the greatest fruit diameter, mesocarp thickness and seed weight per fruit, but the lowest average seed weight and total soluble solids content. Cluster analysis of RAPD data showed a genetic similarity ranging from 88 to 96 % among selections. Late season selections showed less fruit yield and less fruits per tree, but these were top quality fruits. These selections formed a genetically homogenus group based on the cluster analysis. Results emphasize the availability
of selected guava germplasm with high productivity and quality indexes, well adapted to the growing conditions in Mexico.