Analysis on genetic diversification and heterosis in autotetraploid rice

Abstract

Polyploidization has played an important role in plant evolution and is a pathway for plants to increase genetic diversification and to get higher heterosis comparing with that of diploid does. This study was undertaken to assess the genetic variation and relationships among 40 autotetraploid rice genotypes and their counterpart diploid cultivars with 99 SSR markers screened from published rice genome. The 99 SSR markers detected polymorphism among autotetraploid genotypes and revealed a total of 291 alleles with an average of 2.949 alleles per locus. Autotetraploid lines showed higher genetic diversity and significant variation in agronomic traits than diploid cultivars. Phylogenetic analysis revealed that most of autotetraploid lines were genetically different from their diploid parents, and inter-subspecific hybrids were prepared on the basis of genetic distance between parents. Inter-subspecific autotetraploid hybrids showed a higher and positive heterobeltiosis and competitive heterosis than diploid hybrids, especially for grain yield. Genetic distance appeared not to predict heterosis in diploid rice for all traits; however, it showed a significant correlation with grain yield, grain length and grain length to width ratio in autotetraploid rice. This extensive research on autotetraploid heterosis and genetic diversity will be useful for the development of autotetraploid rice hybrids.

Polyploidy enhances F1 pollen sterility loci interactions that increase meiosis abnormalities and pollen sterility in autotetraploid rice

“…We observed abnormal chromosome behavior (e.g. chromosome lagging at metaphases I and II) in a low percentage of PMCs during meiosis, suggesting that interactions between alleles at the Sa, Sb, and Sc loci (Sa Intersubspecific autotetraploid rice hybrids are robust plants with the potential to increase rice yield but suffer from low seed set (He et al, 2011b;Shahid et al, 2013b;Wu et al, 2013). We developed over 1,000 combinations of autotetraploid rice in our laboratory during 2002 to 2010 and found that partial pollen sterility is a major cause of low seed setting in intersubspecific autotetraploid rice hybrids.…”

“…We developed over 1,000 combinations of autotetraploid rice in our laboratory during 2002 to 2010 and found that partial pollen sterility is a major cause of low seed setting in intersubspecific autotetraploid rice hybrids. Furthermore, we found that interactions between different alleles of hybrid pollen sterility loci (Sa, Sb, and Sc) caused low pollen fertility in autotetraploid rice hybrids (Zhao et al, 2006;He et al, 2011b;Wu et al, 2013). It took 4 years to generate the autotetraploid spp.…”

“…indica 3 ssp. japonica) hybrids have biological advantages over diploid hybrids, such as greater adaptability and yield potential Shahid et al, 2011Shahid et al, , 2012Wu et al, 2013). However, because autotetraploid rice hybrids have low seed set, largely because of high pollen abortion rates, it is challenging to produce hybrids with commercially favorable characteristics (He et al, 2011a(He et al, , 2011b.…”

Genetic diversity in mutated and non-mutated rice varieties

“…Eighty seven SSR primers equally distributed on twelve chromosomes (McCouch et al, 2002) were analyzed. The SSR analysis was done as described by Tong et al (2011) and Wu et al (2013). The amplified fragments were electrophoresed on a 1.2% agarose gel at 80 V in 1X TBE buffer (Yang et al, 2012).…”

Prediction of Hybrid Performance in Crop Plants: Molecular and Recent Approaches

“…Many coworkers supported, molecular markers could be used for heterosis prediction (Jaikishan et al, 2010 andSoni et al, 2017), while others disagreed (Chen et al, 2010 andWu et al, 2013). However, technology proven a powerful tool for reliable heterosis prediction.…”