scholarly journals Pollen Grain Number and Viability Contribute to Variation in Effective Ovule Number Among Oilseed Rape Genotypes

2021 ◽  
Author(s):  
Xiao Guo ◽  
Bao-Luo Ma ◽  
Neil B. McLaughlin ◽  
Yajun gao ◽  
Xiaoming Wu ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Critical Period ◽  
Pollen Viability ◽  
Pollen Grain ◽  
Abortion Rate ◽  
Utilization Efficiency ◽  
Grain Number ◽  
Ovule Abortion ◽  
Nitrogen Utilization Efficiency ◽  
Ovule Number

Abstract While no significant differences in initial ovule number were found among oilseed rape genotypes, there was a large variation in effective ovule number (EON), which determines the final seeds per silique (SPS), a critical component of yield. In this study, we selected 18 oilseed rape genotypes with contrasting nitrogen utilization efficiency (NUtE) to unravel the main factors responsible for different EON and determine the critical period of EON formation under both a field and a pot experiments from 2016-2018. The high NUtE genotypes displayed significantly higher NUtE by 14.3%, along with greater yield per plant (29.4%) and SPS (21.1%) than the low NUtE genotypes. The greater productivity of the high NUtE genotypes was associated with 44.1% higher pollen grain number, 23.5% greater pollen viability, and 39.3% lower ovule abortion rate, compared to the low NUtE genotypes. In addition, the heart stage was the critical ovule development period for delineating the variability of EON among contrasting NUtE oilseed rape genotypes, when the high NUtE genotypes displayed higher silique net photosynthetic rate, surface area, biomass, and RNA expression levels. Taken together, this study indicated the pollen grain number, pollen viability and ovule abortion rate contributed to the final variation in EON and the heart stage was the critical period of determining the EON differences among contrasting NUtE genotypes. Increasing pollen grain number and pollen viability, and decreasing ovule abortion rate before heart stage should be the prerequisite for breeders to improve yield and NUtE of oilseed rape genotypes.

Pollen number and vigor contribute to effective ovule numbers among contrasting nitrogen utilization efficiency oilseed rapes genotypes before heart stage

2020 ◽  
Author(s):  
Xiao Guo ◽  
Yuyu Xie ◽  
Yunyou Nan ◽  
Xiaoming Wu ◽  
Biyun Chen ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Critical Period ◽  
Abortion Rate ◽  
Utilization Efficiency ◽  
Ovule Abortion ◽  
Nitrogen Utilization Efficiency ◽  
Ovule Number ◽  
Pollen Number ◽  
Main Factors ◽  
Pollen Vigor

Abstract Background: While no significant differences in initial ovule number were found among oilseed rape genotypes, there was a large variation in effective ovule number (EON), which determines the final seeds per silique (SPS), a critical component of yield. Up to date, on study has been focused on unraveling the pre-flowering main factors to restrict EON and identifying the critical period of EON formation among contrasting nitrogen utilization efficiency (NUtE) oilseed rape genotypes.Results: In this study, we selected 18 oilseed rape genotypes with different NUtE to identify the main factors that contribute to EON, and determine if genotypes differed in the critical period of EON formation under both field and pot experiments from 2016-2018. Our results showed the high NUtE genotypes also showed 14.3% higher NUtE, accompanied with 29.4% higher yield per plant and 21.1% higher SPS. The greater productivity of the high NUtE oilseed rape genotypes was associated with 44.1% greater pollen number, 23.5% higher pollen vigor, and 39.3% lower ovule abortion rate, compared to the low NUtE genotypes. In addition, at the heart stage, the high NUtE genotypes displayed higher silique net photosynthetic rate, surface area, biomass, and RNA expression levels, compared to the low NUtE ones. Taken together, this study indicated the pollen number, pollen vigor and ovule abortion rate contributed to the final EON of diverse oilseed rape genotypes; the critical period of determining EON among contrasting NUtE genotypes was at the heart stage.Conclusion: Increasing pollen number and vigor, and decreasing ovule abortion rate before the heart stage should be the prerequisite for breeders to improve yield and NUtE of oilseed rape genotypes.

scholarly journals Pollen grain number and viability contribute to variation in effective ovule number among oilseed rape genotypes

Euphytica ◽  
2021 ◽  
Vol 218 (1) ◽  
Author(s):  
Xiao Guo ◽  
Bao-Luo Ma ◽  
Neil B. McLaughlin ◽  
Yajun Gao ◽  
Xiaoming Wu ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Pollen Grain ◽  
Grain Number ◽  
Ovule Number

Radiation and nitrogen use at the leaf and canopy level by wheat and oilseed rape during the critical period for grain number definition.

2000 ◽  
Vol 27 (10) ◽  
pp. 899 ◽  
Author(s):  
M. Fernanda Dreccer ◽  
Ad H. C. M. Schapendonk ◽  
Marcel van Oijen ◽  
C. Sander Pot ◽  
Rudy Rabbinge
Keyword(s):  
Vertical Distribution ◽  
Oilseed Rape ◽  
Critical Period ◽  
Plant Density ◽  
Canopy Photosynthesis ◽  
Leaf Photosynthesis ◽  
Grain Number ◽  
N Supply ◽  
Leaf N Content ◽  
Leaf N

During the critical period for grain number definition, the amount of biomass produced per unit absorbed radiation is more sensitive to nitrogen (N) supply in oilseed rape than in wheat, and reaches a higher value at high N. This response was investigated by combining experimental and modelling work. Oilseed rape and wheat were grown at three levels of N supply, combined with two levels of plant density at high N supply. Canopy photosynthesis and daytime radiation use efficiency (RUEA) were calculated with a model based on observed N-dependent leaf photosynthesis and observed canopy vertical distribution of light and leaf N. In oilseed rape, RUEA was higher than in wheat and, in contrast to wheat, the sensitivity to canopy leaf N content increased from the start to the end of the critical period. These results were partly explained by the higher leaf photosynthesis in oilseed rape vs wheat. In addition, oilseed rape leaves were increasingly shaded by the inflorescence. Thus, RUEA increased because more leaves were operating at non-saturating light levels. In both species, the vertical distribution of leaf N was close to that optimising canopy photosynthesis. The results are discussed in relation to possibilities for improvement of N productivity in these crops.

scholarly journals A Duplicated Copy of the Meiotic Gene ZIP4 Preserves up to 50% Pollen Viability and Grain Number in Polyploid Wheat

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 290
Author(s):  
Abdul Kader Alabdullah ◽  
Graham Moore ◽  
Azahara C. Martín
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Wheat Chromosome ◽  
Grain Number ◽  
Meiotic Gene ◽  
Chromosome 5B ◽  
Mutant Pollen ◽  
Female Gametogenesis ◽  
Chromosome 3B

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.

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