The relative sensitivity to plant water stress during the reproductive phase of upland cotton (Gossypium hirsutum L.)

Abstract

The relative sensitivity of the cotton plant to water stress throughout the growing season was determined to identify when irrigation will have the greatest beneficial effect. Daily plant water stress for 72 different data sets of water applications was correlated to corresponding yield criteria. The magnitude of significant correlation was interpreted as the degree of sensitivity. Plant water stress during square formation and early flowering resulted in fewer bolls to reach maturity, but this detrimental effect was cancelled by the development of bigger bolls due to greater lint growth. This resulted in better seedcotton and lint yields. Flower and boll senescence which resulted from water stress during flowering peak, however, inhibited seedcotton and lint yields. The most pronounced inhibiting effect stress had on yields, was during boll development well after the end of effective flowering, when it inhibited boll development. Stress during ripening of the bolls increased lint and boll development and consequently enhanced yields. When limited quantities of water is available, preference should be given to irrigation during boll development, then by irrigation when the first flowers appear, followed by irrigation during peak flowering. Water should be withheld from opening of the first bolls.

Cotton Response to Water Deficits at Different Growth Stages

“…Other authors, such as Wen et al (2013), also affirmed that water deficit in cotton causes boll shedding and thus lower productivity. Loka and Oosterhuis (2012) showed that the reproductive stage is the most sensitive stage to water deficit in cotton, while De Kock, De Bruyn and Human (1993) stated that the peak bloom phase is most sensitive to water deficit, confirming the results found here.…”

Physiological Parameters, Harvest Index and Yield of Deficient Irrigated Cotton

“…However, withholding irrigation for only 2 weeks was enough to reduce yield by 36% (treatment C 7 ). According to Kock et al (1990), the most sensitive growth period to water stress is during peak flowering (90-120 days after emergence). This period fully corresponds with treatment C 7 where irrigation was stopped between days 101 and 115 after seeding.…”

“…Because of the high agricultural value of cotton, research studies were targeted towards the determination of critical growth periods when irrigation is obligatory and water stress should be avoided (Turner et al, 1986;Kock et al, 1990). However, this information regarding the effect of water deficit on cotton is in general not derived from field trials (Devendra et al, 1992;Zhao et al, 1993).…”

Inventing Makhathini: Creating a prototype for the dissemination of genetically modified crops into Africa

“…A minimum of 90-120 mm is then required for seedling development; early water shortages stunt all subsequent growth (Grimes et al, 1969;Stegger et al, 1998). The most sensitive period for water stress is during peak flowering (Kock et al, 1990). Steady, even rains are required: too little inhibits boll formation; too much soaks the roots and damages cotton already on the bolls.…”