Transgressive Segregation, Heterosis and Heritability for Yield-Related Traits in a Segregating Population of Pisum Sativum L.

Abstract

SUMMARYPea is a self-pollinated, diploid (2n = 14), annual crop produced worldwide for human consumption and animal feed. The exploitation of maximum genetic potential from available pea resources implies the knowledge of genetic parameters of yield components. Hence, the present study was conducted in a cross between two pea varieties, namely DDR14 and Explorer, its F2 progeny and F3 families to find out transgressive segregants and to determine the magnitude of narrow sense heritability and heterosis. The high narrow sense heritability values obtained indicated that rapid gain could be achieved through selection for the different traits; however, the presence of genotype x environment interaction could limit the correspondence of these estimated values with the observed ones. The selection of lines through their phenotypic values is influenced by environmental and error effects. Best linear unbiased prediction (BLUP) was used for the prediction of genotypic values using morphological data from different years, allowing the correction for environmental effects. These estimates were used for genetic analysis of the traits. Heterosis was observed for number of pods (27.1%) and number of seeds (23.3%), characters that have a direct effect on yield. The cross also showed high frequency of transgressive segregation for these characters in F3 generation (15.5% and 13.6%, respectively). There were 12.73% families transgressive for two or more characters, with genotypic values of 49.82–64.41 for number of pods and 153.75–189.59 for seed number. The crossing between Explorer and DDR14 provided a base for the selection of superior progeny.

Newly isolated intervarietal garden pea (Pisum sativum L.) progenies (F7) under north western Himalayan conditions of India

“…The interaction of many traits establishes the yield, and hence yield is called a quantitative trait (Guindon et al, 2018). While optimum vegetative growth during crop establishment is required to achieve the maximum yield potential, the desirable plant type in garden pea is the one that has dwarf growth habit and does not need support.…”

“…Heterosis has been predicted in pea long back; however, cleistogamous nature of flower and non-availability of genetic mechanisms like male sterility limit the exploitation of heterosis. Even so, potential crosses likely to produce transgressive segregants could be achieved simply through the selection of superior individual progenies from a range of existing possibilities (Guindon et al, 2018). The success of breeding programme depends on the initial population used or the parents involved to create such populations.…”

Allele specific expression and gene regulation explain transgressive thermal tolerance in non-native hybrids of the endangered California tiger salamander (Ambystoma californiense)

“…Both phenomena are predicted to produce more exaggerated hybrid phenotypes with increasingly divergent parental lineages (Guindon, Martin, Cravero, & Cointry, 2019). Furthermore, heterosis has been used in many studies to predict the successful establishment of transgressive phenotypes in subsequent generations (Chahota, Kishore, Dhiman, Sharma, & Sharma, 2007;Guindon et al, 2019;Khan, Mahbub, Reza, Shirazy, & Mahmud, 2016;Kumar, Jeberson, Singh, & Sharma, 2017). These studies of agricultural crops highlight the importance of examining trait values in the F1 hybrid stage to make meaningful predictions about long-term success.…”

Allele‐specific expression and gene regulation help explain transgressive thermal tolerance in non‐native hybrids of the endangered California tiger salamander (Ambystoma californiense)

“…As recent evidence continues to highlight the importance of epistasis and epigenetics in driving transgressive phenotypes at the F1 stage (Jiang et al, 2017), it is likely that these mechanisms contribute to fixed transgressive phenotypes in admixed populations. Furthermore, in many agricultural studies, the extent of observed heterosis helps predict the successful establishment of transgressive phenotypes in subsequent generations (Chahota et al, 2007; Guindon et al, 2019; Khan et al, 2016; Kumar et al, 2017; Sarawat et al, 1993). In the case of wild non‐native hybrids, it is similarly useful to analyse phenotypic traits in F1 hybrids to understand the potential advantages and adaptations that may arise through transgressive segregation.…”

“…Though often considered separately, heterosis and transgressive segregation are linked processes that can produce transgressive hybrid phenotypes. Both are predicted to produce more exaggerated phenotypes with increasingly divergent parental lineages (Guindon et al, 2019; Stelkens & Seehausen, 2009). As recent evidence continues to highlight the importance of epistasis and epigenetics in driving transgressive phenotypes at the F1 stage (Jiang et al, 2017), it is likely that these mechanisms contribute to fixed transgressive phenotypes in admixed populations.…”