Pollination Requirements of Pigmented Grapefruit (Citrus paradisi Macf.) from Northwestern Argentina

• Published in: Crop science Vol. 47; no. 3; pp. 1143 - 1150
• Main Authors: Chacoff, N.P, Aizen, M.A
• Format: Journal Article
• Language: English
• Published: Madison, WI Crop Science Society of America 01.05.2007; American Society of Agronomy
• Subjects: Agronomy. Soil science and plant productions; apomixis; Argentina; Biological and medical sciences; Citrus paradisi; Cost structure; Crops; Cross-pollination; Cultivars; Cultivated plants; Field study; Flowers; Flowers & plants; fruit set; Fruits; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; grapefruits; inflorescences; Insects; open pollination; plant breeding; Plant reproduction; Pollen; pollen germination; pollen tubes; pollinating insects; Pollination; Pollinators; Reproduction; River basins; seed productivity; selfing; styles; wind pollination; Argentina; South America; America; Pollinator; Citrus fruit; Dicotyledones; Angiospermae; Rutaceae; Citrus paradisi; Grapefruit; Spermatophyta; Pollination
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2006.09.0586

The consequence of a proposed pollinator decline for agriculture is a subject of much ongoing debate. However, pollination requirements of many cultivated plants remain unknown. Citrus is complex in terms of pollination needs because of great variation in breeding systems among and within species, and even among and within cultivars. The objective of this study was to evaluate pollinator dependence of three cultivars of grapefruit (Citrus paradisi Macf.) planted in northwestern Argentina. Bagged flowering branches were assigned to different pollination treatments: emasculation, spontaneous self-pollination, hand self-pollination, and hand cross-pollination, and the results compared with those from open-pollinated flowers. We counted the number of pollen grains and pollen tubes in the style, fruit set, and seed production. We also assessed differences in germination rates of self- vs. cross-pollen grains. We found that hand- and open-pollinated flowers set about six times more fruit than emasculated and bagged (insect excluded) flowers. In addition, cross-pollen performed better in terms of grain germination and tube growth than self-pollen. Although being fully self-compatible, apomixis and wind pollination are not important factors for grapefruit reproductive success. Thus, insect pollinators represent a critical and potential limiting resource for seedless grapefruits from northwestern Argentina.