Abstract Detail

Physiology

Wood, Joseph B. [1], Cramer, Christopher [1], Steiner, Robert [2], Schutte, Brian J. [3], Heerema, Richard [1], Guzman, Ivette [4].

Allium Physiological Response to Biotic and Abiotic Stress.

Bulb onion is an economically valuable vegetable crop in the U.S. valued at around $1 billion annually. Many pests plague onion farmers but Iris yellow spot virus (IYSV) has been identified as a major cause of economic loss. IYSV is in the genus Tospovirus, family Bunyaviridae, and is present in most allium growing regions in the world. Onion thrips (Thrips tabaci) are the primary vector for IYSV in onions and are increasingly difficult to control. These insects cause a substantial amount of physical which, compounded with the stress caused by the virus, can prove detrimental to the onion plant. The objectives of this project are to further understand how IYSV and drought stress affect onion physiology in order to produce onions more efficiently. We conducted a field study using four onion cultivars bred at NMSU as well as a commercial cultivar. All onions were subjected to high virus pressure and half were subjected to drought stress while the other half were given sufficient water. Gas exchange, chlorophyll fluorescence and leaf area index were measured for each cultivar using an LI-6800 and an LAI meter every two weeks for eight weeks. The carbon assimilation rates of the NMSU bred cultivars were compared to the commercial cultivar within treatments as well as by cultivar across treatments. Some of the NMSU bred onions had higher assimilation rates than the commercial cultivar at weeks 10-14 in both the drought stressed and well-watered treatments. This is likely due to an increase in resistance to IYSV present in the NMSU bred onions. The well-watered onions also had higher assimilation rates than the drought stressed onions in 2019, suggesting that drought stress may exacerbate the effects of the virus. By week 16 all onions exhibited similar assimilation rates because they were going dormant. By understanding the relationship between IYSV, drought stress and the onion, the disease can be more efficiently mitigated to prevent economic losses.

1 - New Mexico State University, Plant and Environmental Science, MSC 3BE , Las Cruces, NM, 88003, USA
2 - New Mexico State University, Applied Statistics, 1320 E University Ave, Las Cruces, NM, 88003, USA
3 - New Mexico State University, Entomology, Plant Pathology and Weed Science, MSC 3BE, Las Cruces, NM, 88003, USA
4 - New Mexico State University, Plants And Environmental Sciences, 945 College Drive, Las Cruces, NM, 88003, United States

Keywords:
onion physiology
Photosynthesis
chlorophyll  fluorescence  
Drought
Iris Yellow Spot Virus.

Presentation Type: Oral Paper
Session: PHYS, Physiology
Location: /
Date: Wednesday, July 21st, 2021
Time: 1:45 PM(EDT)
Number: PHYS012
Abstract ID:746
Candidate for Awards:Physiological Section Physiological Section Li-COR Prize,Physiological Section Best Paper Presentation