Plant Density Influences Reproductive Growth, Lint Yield and Boll Spatial Distribution of Cotton

Abstract

The number of cotton plants grown per unit of ground area has gained attention due to the high prices of inputs and lower production. Cotton yield per unit of area in Henan province has been stagnant in the last few years. The objectives of this study were to investigate cotton growth, yield, boll spatial distribution and biomass accumulation using different plant densities at cultivation and to find out the optimal plant density. A 2-year field experiment was conducted in a randomized complete block design under six plant densities (D1, 15,000; D2, 33,000; D3, 51,000; D4, 69,000; D5, 87,000 and D6, 105,000 ha−1). Cotton grown at lower plant density produced taller plants and high number of leaves per plant while greater number of branches, fruiting nodes and high number of bolls per unit of ground area were produced under high plant density. Boll retention rate decreased as plant population increased and at nodes 1–8 the rate decreased slowly and then increased dramatically. The highest seed cotton yield (4546 kg ha−1) and lint yield (1682 kg ha−1) was produced by D5. The seed cotton and lint yield produced by D5 were 51–55%, 40–37%, 22–26%, 11–15%, 12–15%, 28–30%, 21–24%, 15–20%, 7–13% and 13–17% higher than D1, D2, D3, D4 and D6 during both years of experimentation, respectively. The increase in seed yield was due to higher biomass accumulation in reproductive organs under D5 plant density. The highest average (110.4 VA kg ha−1 d−1) and maximum (126 VM kg ha−1 d−1) rate of reproductive organs biomass was also accumulated by D5 as compared to other plant densities. The results suggest that D5 is the optimal plant density for high reproductive biomass accumulation and high yield for the area of Henan province.

Opportunities and challenges of speed breeding: A review

“…In a contrasting sorghum study by Villar et al (1989), increasing plant density from 16 to 38 plant m -2 reduced the days to flowering from 59 to 50 days. In cotton, high-density planting (11 plant m -2 ) slightly reduced flowering to 25-26 days from 26-31 days c with lower density planting (9 plant m -2 ) (Khan et al, 2017(Khan et al, , 2019.…”

“…(1989), increasing plant density from 16 to 38 plant m ‐2 reduced the days to flowering from 59 to 50 days. In cotton, high‐density planting (11 plant m ‐2 ) slightly reduced flowering to 25–26 days from 26–31 days c with lower density planting (9 plant m ‐2 ) (Khan et al., 2017, 2019). The above studies suggest that genotype differences affect plant responses to high‐density planting under field conditions.…”

Planting geometry of cotton under rain fed condition in the dry land areas of western Tigray

“…The same authors added that cotton in narrow row spacing produced particular greater dry mass compared to the conventional system. Higher seed cotton yield was recorded in the narrow plant spacing compared to a wider spacing and increased bolls at the 1st, 2nd and 3rd positions of the plant with less yield and unnecessary vegetative growth that led to undesirable fruit shedding was observed in the wider spacing (Khan et al, 2020). Similarly, Clark and Carpenter (1992) reported higher seed cotton yield in narrow row spacing compared to wider inter row.…”

Irrigation-Water Management and Productivity of Cotton: A Review

“…For instance, the plant density is 12.6 plants per m 2 in Georgia [113], 15.3 plants per m 2 in Louisiana [114], 6.6 plants per m 2 in Mississippi [115], and 10.0 plants per m 2 in Arizona [116]. In China, Khan et al [117] carried out a study using six different densities and stated that taller plants and a higher number of leaves per plant were obtained with cotton cultivated at a lower plant density, while, under a high plant density, a higher number of branches and fruiting nodes and a greater number of bolls per unit of soil area were observed. The authors further revealed that the highest seed cotton yield (4546 kg ha −1 ) and lint yield (1682 kg ha −1 ) were produced by "D5" (87,000 plant ha −1 ).…”