Author Archive Kaye1214

Developing Screening Tools for Early-season High- and Low- Temperature Stress Tolerance in Rice

S.H. JUMAA1, E.D. REDOÑA2, T. WALKER3, W. GAO and K.R. REDDY1*

      1Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
      2Delta Research and Extension Center, Mississippi State University, PO Box 197, Stoneville, MS 38776, USA.
      3Horizon Ag. LLC, 8275 Tournament Drive, Suite 255, Memphis, TN 38125, USA.
      4USDA-UVB Monitoring and Research Program, Natural Resource Ecology Laboratory, and Department of Ecosystem Science and Sustainability, Colorado State University, Fort Collins, CO 80523, USA
      *Corresponding author’s email: krreddy(at)pss.msstate.edu
      Email addresses of coauthors: shj44(at)msstate.edu, EdRedona(at)drec.msstate.edu, twalker(at)horizonseed.com, Wei.Gao(at)colostate.edu

Download pdf copy

Summary

Temperature is one of the key abiotic stress factors that affect various stages of plant growth and development. In the US Midsouth, rice plants get exposed to variable temperatures depending on the planting date. We hypothesize that rice cultivars vary in their response to temperature, and developing a method for low- and high-temperature tolerance screening will help producers and breeders to select cultivars for management and breeding, respectively. Four rice cultivars, CL152, Bowman, Antonio, and Mermentau along with two hybrids XL 753 and CLXL 745 that were the most commonly grown in the US Midsouth were evaluated in this study for temperature tolerance. Five day/night temperature treatments, 20/12 (very low), 25/17 (low), 30/22 (optimum), 35/27 (high), and 40/32 °C (very high) were imposed after the seedling establishment, ten days after planting (DAP). Growth and developmental parameters including root and physiological parameters were recorded from plants harvested at 39 DAP. Rice cultivars and hybrids exhibited significant variability in their response to low and high temperatures. Based on total low- and high-temperature response indices, relative temperature response scores were derived. Total low-temperature response index values ranged from 18.48 to 23.15 whereas total high-temperature responses index values ranged from 42.01 to 48.82. Antonio, CLXL 745, and Mermentau were identified as sensitive to cold and heat, Bowman as sensitive to cold and moderately sensitive to heat, CL152 was moderately sensitive to cold and heat, and XL 753 was highly cold and heat tolerant cultivars/hybrids tested. These results may be useful for breeders to develop new rice cultivars which could withstand low- and high-temperature conditions during seedling stages. Further large-scale studies are needed to evaluate more cultivars or lines both in the controlled environments and field settings to come up with practical recommendations.

Key words: Rice (Oryza sativa L.), temperature, morpho-physiological parameters, root growth and developmental traits, SPAR, Total Drought Response index (TDRI), TLTRI, Total low temperature response index; THTRI, total high temperature response index; SD, standard deviation; r2, coefficient determination; PH, plant height; TN, tillers number; LN, leaves number, LA, leaf area; LW, leaf weight; SW, stem weight; RW, root weight; AGW, above ground weight; TW, total weight; RS, root/shoot; RL, root length; RSA, root surface area; RAD, root average diameter; RV, root volume; RNT, number of tips; RNF, number of forks; RNC, number of crossing; SPAD, chlorophyll content; Fv’/Fm’, fluorescence

Key findings: Temperature affects all shoot, root and physiological parameters. Cultivar differences were observed for low and high-temperature responses during the early-season.

Download pdf copy

Tags, ,

Determination of lethal dose and effect of gamma rays on growth and tuber yield of Jerusalem artichoke mutant

Download pdf copy

P. SONGSRI1, S. JOGLOY1,2, C.C. HOLBROOK3 and D. PUANGBUT4*

      1Department of Agronomy, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
      2Peanut and Jerusalem Artichoke Improvement for Functional Food Research Group, Khon Kaen University, Khon Kaen, Thailand
      3Crop Genetics and Breeding Research Unit, USDA-ARS, Tifton, Georgia, USA
      4Plant Production Technology, Faculty of Technology, Udon Thani Rajabhat University, Udon Thani, Thailand
      *Corresponding author’s email: daruneepom(at)gmail.com
      Email addresses of coauthors: psongsri(at)gmail.com, sanjogloy(at)gmail.com, corley.holbrook(at)ars.usda.gov

SUMMARY

Mutation induced by radiation may result in increased variation in Jerusalem artichoke. The objective of this study was to determine the LD50 and effect of gamma rays on growth and tuber yield of two Jerusalem artichoke genotypes HEL 65 and CN 52867. The experimental design was a completely randomized design (CRD) with 4 replications. The results demonstrated that LD50 for the genotypes HEL 65 and CN 52867 were 22 and 27 Grays (Gy), respectively. The radiation treatments did not change flower characters in either genotype. Germination percentage and plant height in both genotypes were decreased by increasing the radiation dose. In contrast, the number of branches was increased with higher gamma radiation doses (20 and 25 Gy). Gamma ray radiation at 5 Gy increased tuber yield in both Jerusalem artichoke genotypes. The present study indicated that gamma radiation might be useful for improvement of important traits such as yield in Jerusalem artichoke.
 
Key words: Helianthus tuberosus L., irradiation, plant height, fresh tuber yield

Key findings:
The LD50 for Jerusalem artichoke genotypes HEL 65 and CN 52867 were 22 and 27 Gy, respectively. Plant height and germination percentage decreased with increasing doses of gamma rays. Low dose at 5 Gy could be used to increase tuber yield of these two genotypes of Jerusalem artichoke.

Download pdf copy

Tags,