Abstract Detail

Crops and Wild Relatives

Chacon, Francisco [1], Cramer, Christopher [1], Guzman, Ivette [1].

Leaf Area Index as an Indicator of Phenology and Dormancy in Allium cepa (L.).

Onion is an important culinary ingredient that has been in domestication for over 4000 years. They are monocots and belong in the Liliaceae family within the Allium genus. Currently more than 800 species have been identified in the genus Allium. Domesticated or garden bulb onions are classified as A. cepa Linn. In 2019, the United States harvested about 129,400 acres and produced 7.8 billion pounds. New Mexico ranks fifth in the nation for bulb onion production. Onions are biennial plants relying on a dormancy period between the first season and second season. The first season is dedicated to vegetative and bulb growth while the second season is dedicated to reproductive growth. Dormancy periods and growth rates vary depending on the cultivar, biotic and abiotic stress conditions. The objective of this study was to evaluate leaf area index (LAI) as a non-destructive measurement of onion growth and development in multiple Allium cepa cultivars grown under two different watering treatments. Leaf area index is a measurement of canopy and is derived by integrating the leaf area density over canopy height. The onions were seeded in a greenhouse and once large enough, they were transplanted in a split plot design at the New Mexico State University Fabian Garcia Science Center field. Two irrigation treatments were applied, a water sufficient treatment and a water deficit treatment. Using a ceptometer, LAI was measured every two weeks over an eight-week period for both irrigation treatments. The hypothesis was that LAI would positively correlate with onion development in a field study growing onions under two watering treatments. The results indicated that as the onions approached dormancy, LAI values decreased significantly in all cultivars. There were also significant differences in LAI values between treatments, indicating that the water deficit plants always had lower LAI values than the well-watered plants. Therefore, the hypothesis was proven correct indicating that LAI can be used by growers to monitor maturity of onions in the field as they approach dormancy. Due to the fact that not much is known about how the environment can trigger onion dormancy, our study not only correlates water availability to dormancy, but also provides a simple low maintenance method for tracking onion phenology from seed to dormancy.

1 - New Mexico State University, Plant and Environmental Sciences, 945 College Drive, Las Cruces, New Mexico, 88003, United States

Keywords:
onion
dormancy
biennial
Allium
leaf area index
phenology.

Presentation Type: Poster
Session: P, Crops and Wild Relatives Posters
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 5:00 PM Time and date to be determined
Number: PCW001
Abstract ID:712
Candidate for Awards:None