Effect of Shading on Cotton Yield and Quality on Different Fruiting Branches

Abstract

Reduced radiation from air pollutants has become a major challenge to cotton (Gossypium hirsutum L.) production. Field experiments were conducted using two cotton cultivars at three shading levels during boll development in Nanjing (32°02′ N, 118°50′ E), China, to determine the effect of shading on cotton yield and quality. Lint yield, distributions of yield within the plant and that of biomass within bolls, and the quality of fiber and seed were analyzed. Shading reduced lint yield (decreased by 17–22% and 35–38% under shading conditions S1 and S2, respectively) through reducing boll number and boll weight, but increased proportion of lint yield on the bottom five fruiting branches (FB1–5) by 2.1 to 2.4% and 3.4 to 4.3% under S1 and S2, respectively. The proportion of fiber biomass in the boll decreased significantly, whereas proportion of seed biomass increased with enhanced shading. Fiber was the most sensitive boll component to shading, the biomass of which under shading condition (S1, S2) decreased by 5.9 to 6.9% and 8.8 to 11.9%, respectively. Shading increased oil content but decreased protein content of the seed on FB3. Seed oil and protein contents on FB7 and FB12 responded opposite to those on FB3. Simultaneously, shading was advantageous to fiber length and micronaire but disadvantageous to fiber strength. The greater the shading enhanced, the more the abovementioned measurements were affected. Shading due to air pollutants alters biomass distribution within bolls and lint yield distribution within the plant. Bolls on the bottom fruiting branches are more tolerant of shading.

Cotton yield and fiber quality affected by row spacing and shading at different growth stages

“…Among the different yield components, the number of bolls is most affected by shading, with decreases of 13-40% relative to unshaded controls (Pettigrew, 1994;Zhao and Oosterhuis, 2000). The abscission percentage is higher when shading is imposed during fruit filling, and Lv et al (2013) observed a decrease in boll number, boll weight and cotton yield when shading occurred at the onset of flowering. Although the effects of shading on cotton yield and fiber quality are known, most of these studies were conducted in temperate regions where the growing season is short and yields cannot be recovered with an eventual lengthening in cotton growing season.…”

“…However, the leaf planophile structure can result in a strong light gradient within the canopy specially in high plant populations (Dauzat et al, 2008). In this case, little light reaches the bottom leaves (Lv et al, 2013).…”

Effect of late planting and shading on cotton yield and fiber quality formation

“…Late-planting usually resulted in reducing yield with low lint percentage and boll weight relative to normal planting (Arshad et al, 2007;Gwathmey and Clement, 2010), and shading usually resulted in reducing yield through reducing boll number and boll weight (Zhao and Oosterhuis, 2000;Dusserre et al, 2002;Lv et al, 2013). In this study, as shown in Tables 2 and 3, when averaged the data of years and cultivars, it was observed that boll number per hm −2 , boll weight and lint yield decreased in the late-planted a VRG and VSG, mean strengthen rate of rapid growth and steady growth period of fiber strength, respectively.…”

“…Shading decreased net photosynthetic rate and enzyme activities that participate in the Calvin cycle in cotton leaf (Zhao and Oosterhuis, 1998;Pettigrew, 2001), reduced the assimilate supply, and decreased lint yield and fiber quality consequently. Boll number was the most sensitive yield component to shading (Zhao and Oosterhuis, 2000;Lv et al, 2013). Boll weight was also decreased through reducing carpel growth, fiber biomass maximum increase rate and fiber final biomass (Dusserre et al, 2002).…”

“…However, the response of fiber quality to shading didn't have come to an agreement because of timing and duration of shading (Zhao and Oosterhuis, 1996). Cotton had fiber with lower strength and micronaire, while fiber length decreased or increased under shading conditions (Zhao and Oosterhuis, 2000;Wang et al, 2006;Lv et al, 2013).…”