Genotypic variance in 13C-photosynthate partitioning and within-plant boll distribution in cotton

Junjun Nie,Xuezhen Sun,Hezhong Dong,Xianliang Song,Lili Mao,Yanhui Liu,Dulin Qin

doi:10.1186/s42397-020-00055-3

Junjun Nie, Xuezhen Sun + Show 5 more

Open Access

https://doi.org/10.1186/s42397-020-00055-3

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Abstract

BackgroundPhotosynthate partitioning and within-plant boll distribution play an important role in yield formation of cotton; however, if and how they interact to mediate yield remains unclear. The objective of this study was to investigate the genotypic variance in photosynthate partitioning and within-plant boll distribution, with a focus on their interactions with regard to yield and yield components. A field experiment was conducted in the Yellow River region in China in 2017 and 2018 using a randomized complete block design with three replicates. Photosynthate partitioning of three commercial cultivars (DP 99B, Lumianyan 21 and Jimian 169), varying in yield potential, to different organs (including bolls) at early flowering, peak flowering, and peak boll-setting stages, as well as within-plant boll distribution at harvest, and their effects on yield formation were examined.ResultsLint yield of Jimian 169 was the highest, followed by Lumianyan 21 and DP 99B. Similar differences were observed in the number of inner bolls and boll weight among the three cultivars. J169 partitioned significantly more photosynthate to the fruit and fiber than Lumianyan 21 and DP 99B and allocated over 80% of assimilates to the inner bolls. Additionally, Lumianyan 21 allocated a higher proportion of photosynthate to bolls and fiber, with 12.5%–17.6% more assimilates observed in the inner bolls, than DP 99B.ConclusionsGenotypic variance in lint yield can be attributed to differences in the number of inner bolls and boll weight, which are affected by photosynthate partitioning. Therefore, the partitioning of photosynthate to fiber and inner bolls can be used as an important reference for cotton breeding and cultivation.

Highlights

Photosynthate partitioning and within-plant boll distribution play an important role in yield formation of cotton; if and how they interact to mediate yield remains unclear
Our previous study on the relationship between yield formation and within-plant boll distribution suggested that the main reason for the increase of lint yield of newly bred cultivars was the increase of boll weight and the number of inner bolls (Nie et al 2019)
Experimental materials Three commercial Bt cotton cultivars, which are local to and prevalent in the Yellow River region in China, were selected: (1) DP 99B (99B), a mid-season conventional cultivar introduced from the United States, with a growth period of approximately 130 days, boll weight of 4.9–5.5 g, and lint percentage of 36.0%–38.8%; (2) Lumianyan 21 (L21), the first era mid-season conventional cultivar bred by Chinese breeders, with a growth period of approximately 133 days, boll weight of 5.8 g, and lint percentage of 41.6%; and (3) Jimian 169 (J169), the second era mid-season conventional cultivar bred by Chinese breeders, with a growth period of 123 days, boll weight of 6.3 g, and lint percentage of 39.4%

Summary

Introduction

Photosynthate partitioning and within-plant boll distribution play an important role in yield formation of cotton; if and how they interact to mediate yield remains unclear. Our previous study on the relationship between yield formation and within-plant boll distribution suggested that the main reason for the increase of lint yield of newly bred cultivars was the increase of boll weight and the number of inner bolls (Nie et al 2019). These findings illustrate that the main factor affecting yield formation has changed as a result of the selection for increased lint yield.

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