Submitted to: Laboratory Publication
Publication Type: Research Notes
Publication Acceptance Date: 10/1/2005
Publication Date: 10/1/2005
Citation: Mills, N.B., Oosterhuis, D.M., McMichael, B.L. 2005. Effects of early-season adverse conditions on root development and the subsequent stress. Summaries of Arkansas Cotton Research 2004[medium]. Research Series 533. Fayetteville, AR: University of Arkansas. Interpretive Summary: Cotton grown in the Mississippi Delta is generally planted into cool wet soil resulting in poor germination, slow root development and overall reduced plant establishment. A study was conducted to determine the response of four genetically diverse cultivars to low temperatures in terms of differences in early root growth in order to assess any tolerance that may be present. Significant differences in root development were observed between the cultivars tested particularly at the low (59 F) temperatures. These results suggest the possibility for breeding for low temperature tolerance in future cotton varieties.
Technical Abstract: Cotton (Gossypium hirsutum L.) grown in the Mississippi River Delta is generally planted in cool and wet weather conditions that lead to slow germination, uneven emergence, and poor root growth. The optimum temperature for cotton root development is reported to be 28°C. The base temperature for plant growth is generally accepted as 15.5°C and the minimum temperature for cotton germination to be near 12°C. However, low temperature during the initial growth stage is a problem that affects all cotton cultivars produced across the Mississippi Delta. This research showed that root growth response to temperature exists among the four diverse cultivars culminating in various growth patterns to the temperature regimes. Cultivar Stoneville 4892BR had the most sizeable root growth over the entire range of temperature regimes while Tamcot Sphinx had the most predictable growth pattern with peak growth at 15°C to 35°C. Root dry weight was proportional to root length among cultivars. Cotyledon dry weight exhibited no association with root length or root dry weight. Genotypic differences for root development between cotton cultivars can be examined to find a cultivar able to withstand cool temperatures and produce a vigorous root system for a more healthy plant and yield stabilization.