Since the founding of the People’s Republic of China in 1949, significant achievements have been made in cotton production in China.  China has maintained its position as the world’s largest cotton producer for 33 years (1983–2015), with average annual increases of 3.5 and 3.9% in the unit yield and total output of cotton, respectively.  Cotton production has played an extremely important role in the development of the national economy and the improvement of living standards.  Although the cotton planting area has been reduced in recent years, the total output has remained relatively unchanged due to the continuous increase in the unit yield.  China’s dominant position in global cotton production is undoubtedly attributed to the progress and development of cotton cultivation technology.  Over the past 70 years, China has established a high-yielding and high-efficiency cotton cultivation mode that corresponds to its national conditions, including a large population and a limited land area.  Furthermore, cotton cultivation technology is constantly being innovated and developed to keep pace with the times.  In this paper, we review the development of cotton production and cultivation in China over the past 70 years, with a particular focus on the innovation and development of cotton cultivation technology with Chinese characteristics.  This review is intended to provide guidance for the sustainable development of China’s cotton production in the future and to provide a reference for global cotton production.

Topping is a cultivation method that is widely practiced due to the indeterminate growth character of cotton (Gossypium hirsutum L.).  Among the different methods of accomplishing topping, manual topping is common in the Yellow River Valley of China, although it is time- and labor-intensive.  The objective of this study was to characterize the responses of cotton to different topping treatments with respect to development, yield and quality.  This study included field experiments from 2015 to 2016 with three different topping methods: manual topping (MT), chemical topping (CT) using mepiquat chloride, and a non-decapitation treatment (NT).  We found that the plant height, the number of fruiting branches and the length of upper fruiting branches of cotton treated with CT were significantly lower than NT.  The chlorophyll content of cotton treated with CT was not significantly different from NT, but was higher than that of MT in the later season.  CT enhanced plant development with reduced endogenous gibberellic acid and abscisic acid contents, and the apical development of the main stem was inhibited.  Compared with MT, CT significantly increased the biomass of the vegetative parts.  Most importantly, there were no significant differences in the yield or fiber quality between MT and CT.  These findings suggested that CT, a simplified and effective topping method, could be utilized as an alternative in the Yellow River Valley of China.

Tree peony seed is unique for its super-high content of unsaturated fatty acid and is thus considered as an important
source of woody oil. However, photosynthetic production is greatly reduced under high light intensity and air temperature
during the seed filling period, which negatively affects seed yield and quality. The objective of this study was to determine
if appropriate shading improves yield and quality of seed in oilseed peony. In this study, oilseed peony trees were shaded
by different density polyethylene nets from four weeks after flowering to harvest stages to form light, moderate, and severe
shadings, equivalent to about 80, 40, and 20% of full solar exposure, respectively. The effects of different shadings on
some physiological parameters, yield and yield components, and nutritional composition of seed were examined. Averaged
across two years, light shading increased the actual net photosynthetic rate (Pn) by 16.8%, the maximum net photosynthetic
rate (Pmax) by 81.4%, chlorophyll (Chl) content by 52.8%, auxin (IAA) content by 38.1%, and gibberellic acid (GA3) content
in leaves by 6.3%; it decreased the accumulation of H2O2 in leaves by 24.8%, malondialdehyde (MDA) by 22%, and
endogenous abscisic acid (ABA) by 8.8%, indicating that leaf senescence in late season was considerably delayed. Light
shading increased seed yield, and contents of crude fat and unsaturated fatty acids by 9.7, 5.6, and 9.6%, respectively,
while moderate or severe shading significantly reduced all the three parameters. Light shading increased seed weight,
but moderate or severe shading reduced seed weight or follicle density. The improved seed yield under light shading was
mainly due to increased seed weight, while the reduced seed yield under moderate or severe shading was mainly attributed
to reduce follicle density and seed weight. The improved seed weight and content of unsaturated fatty acids under light
shading was possibly due to the delayed leaf senescence. The overall results indicated that light shading is beneficial to
yield and quality parameters of seed in oilseed peony. Cultivating oilseed peony under a light shading environments such as
partially closed forests would better increase total output and income per unit land area than that under full solar exposure.