Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: 7/15/2004
Publication Date: 9/19/2004
Citation: Jenderek, M.M. 2004. Cladode and flowering characteristics of the USDA Opuntia sp. germplasm collection. AAIC. P. 46 Interpretive Summary: NA. Abstract only.
Technical Abstract: Plants of several Opuntia species are used as fruit, vegetable, fodder for livestock, and as raw material for cosmetic, pharmaceutical and construction industries. The cactus may be grown in arid and semiarid environments on marginal soils. Various cultivars, particularly in the species O. ficus-indica, are already grown commercially in the U.S., Israel, Italy, Mexico and South Africa. The need for new sources of genetic diversity and subsequent germplasm evaluations is more and more apparent. Until recently, however, no publicly maintained germplasm collection of Opuntia existed in the U.S. The objective of this study was to evaluate the morphological characteristics of selected Opuntia accessions maintained in the USDA collection, and to determine the diversity in the collection. In 2003 and 2004, five plants from 49 different accessions were evaluated for flower and cladode characteristics under the San Joaquin Valley climate conditions. These clones, originated from local wild populations, home gardens, and the TA&M University-Kingsville, TX. The time of initial flowering ranged from the end of March (PARL 200 and 203) to the end of June (PARL 296 and 297). In the second flush of flowers the number of flowers/plant varied from 0 to 142 (PARL 227) and 150 (PARL 231). The flower petal colors observed were different shades of yellow (15 accessions), orange (8 accessions), and red (8 accessions). Plants of 16 accessions did not flower in either of the evaluation seasons. A cladode size index (length x width x thickness/width at the cladode base) varied from 75.5 (PARL 233) to 472.2 (PARL 228), and the cladode color was from light green to blue - green. The susceptibility of plants to frost and/or mechanical damage varied from 0 (none) (PARL 201, 229, and 234) to 2.8 (PARL 263; rank 3 being the highest). The level of natural infection by scale (Aspidiotus nerii) insects ranged from 0 (6 accessions) to 3 (2 accessions). The lowest number of spines/cladode was observed in PARL 235 (1 aerole/25 cm2 of cladode); however, its spines were the longest (119 mm). The shortest spines grew on PARL 242 (1.7 mm) and PARL 261 (1.8 mm). Spines of 32 accessions were ranked as brittle in appearance. The evaluation of Opuntia fruit quantity and quality together with the cladode traits and flowering ability continues and ultimately will aid in the selection of germplasm for a future cultivar development. The first USDA, NPGS Opuntia sp. germplasm collection is diverse in regard to flowering time, flowering abundance, cladode size and appearance, and the susceptibility to scale insect infestation.