Evidence for Heterosis in Italian Ryegrass (Lolium multiflorum Lam.) Based on Inbreeding Depression in F2 Generation Offspring from Biparental Crosses

Wang, Junping; Pembleton, Luke W.; Cogan, Noel O. I.; Forster, John W.

doi:10.3390/agronomy6040049

Cited by 16 publications

(14 citation statements)

References 30 publications

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“…Posselt [7] demonstrated a significant positive correlation between forage yield of perennial ryegrass hybrids and the geographical distance between their parental populations. On the other hand, genetic relationship between parents used for F 1 hybrid production was not significantly correlated with heterosis for total herbage yield in hybrids of Italian ryegrasses [8]. Similarly, geographical distance between two parents presumably reflecting genetic relationship does not always correlate with heterosis.…”

Section: Introductionmentioning

confidence: 76%

Extraordinary Heterosis Found In A Forage Grass Hybrid, Festuca apennina × F. pratensis

Boller¹,

Kopecký²

2020

Preprint

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Background: Heterosis (or hybrid vigor) is the over-performance of a hybrid over its parents in a specific trait or a set of traits. As such, hybrid breeding serves as a tool to efficiently trigger gains in breeding programs. Moreover, hybrids of genetically distant landraces, varieties or even species may become evolutionary successful. In Swiss alpine swards, we observed frequent prevalence of triploid hybrids of Festuca pratensis × F. apennina with outstanding competitiveness relative to their parental species in the sites of sympatric occurrence. Results: Observations of these highly vigorous hybrids prompted the study on their heterosis across various environmental conditions. Phenotypic observations during three years at four locations at different altitudes (from 200 m a.s.l. to 1850 m a.s.l.) have shown significant heterosis for dry biomass production at all sites during the first and second year, and at the mid- and high altitude sites also in the third year. At mid-altitude (1000 m a.s.l.), heterosis increased steadily and reached a maximum of +508 % for annual yield (+626% for a single cut) in the third year. This is by far the highest value of heterosis ever reported for annual dry mass yield of a forage grass. Conclusions: Further utilization of triploid hybrids in forage grass breeding is hampered by their sterility hence a need for vegetative propagation. However, artificial chromosome doubling of triploids to create fertile hexaploids, or seeking ways to propagate them vegetatively at an industrial scale might overcome this limitation.

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Section: Introductionmentioning

confidence: 76%

Extraordinary Heterosis Found In A Forage Grass Hybrid, Festuca apennina × F. pratensis

Boller¹,

Kopecký²

2020

Preprint

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“…In the present study weak associations were found between phenotypic distance with yield performance and drought tolerance. In tall fescue and Italian ryegrass phenotypic selection of parents was not feasible for improvement of yield (Amini et al, 2016;Wang, Pembleton, Cogan, & Forster, 2016). The efficiency of parental selection based on phenotypic traits may be limited because they are under great influence of the environment, presence of genotype × environment interactions and an unknown mechanism of genetic control (Amini et al, 2016;Pavani, Sundaram, Ramesha, Kavikishor, & Kemparaju, 2018).…”

Section: Discussionmentioning

confidence: 99%

Genotype selection for physiological responses of drought tolerance using molecular markers in polycross hybrids of orchardgrass

2019

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The present study aimed to assess the effect of contrasting levels of molecular and phenotypic diversity among polycross parents of orchardgrass on the performance of synthetic progeny with respect to physiological responses and drought tolerance. Four polycross groups each composed of six parental plants were evaluated under normal irrigation and drought stress conditions. A number of 923 inter simple sequence repeats and sequence related amplified polymorphism markers and several phenotypic traits were used to select contrasting levels of diversity (high and low) in parental genotypes. Highly significant correlation was observed between molecular distance and progeny performances at both normal irrigation and drought stress conditions. High molecular diversity among polycross parents led to a significant yield advantage of first generation progeny with averages of 34.40% for normal irrigation and 48.10% for drought stress conditions. Also crosses between genetically distant parents produced progeny with considerable drought tolerance and yield stability. Positive associations between phenotypic distance of parents and progeny performance were found for most physiological traits at both moisture regimes but phenotypic distances had weak association with forage yield, stress tolerance index and yield stability of progeny. Significant associations between drought tolerance index and some physiological traits confirmed the importance of these traits in conferring drought tolerance of orchardgrass. Our results underscore the effectiveness of marker‐assisted polycross breeding to improve drought tolerance and yield stability through physiological traits in orchardgrass.

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“…Inbreeding depression in L. perenne has been observed for plant dry weight and seed vigour after one generation of inbreeding by Bean and Yok‐Hwa (). In Italian ryegrass, Wang, Pembleton, Cogan, and Forster () also reported a significant depression for herbage yield from F 1 to F 2 generation. According to these results, the dominant reproduction mechanism in L. perenne seems to be outbreeding; however, a high rate of inbreeding can be observed under the selective conditions (possibly in endophyte‐infected status) within a limited set of selected elite parents.…”

Section: Introductionmentioning

confidence: 88%

“…Inbreeding depression in L. perenne has been observed for plant dry weight and seed vigour after one generation of inbreeding by Bean and Yok-Hwa (1972). In Italian ryegrass, Wang, Pembleton, Cogan, and Forster (2016) also reported a significant depression for herbage yield from F 1 to F 2 generation.…”

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confidence: 97%

A simultaneous effect of selfing and Epichloë endophyte on forage, seed yield and turf characteristics of perennial ryegrass (Lolium perenne L.)

Torkian

Rahimmalek

Ehtemam

2019

Grass and Forage Science

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Ryegrass (Lolium perenne L.) is a putative turf and forage plant characterized as mainly outcrossing in which the extent of self‐fertilization and its consequences has not been investigated. In this study, selfed and half‐sib family seeds were obtained from ten clonally propagated ryegrass plants among which two were endophyte‐free (EF) and eight were endophyte‐infected (EI). Then, 20 seed populations plus two commercial varieties of Speedy and Vigor were sown and evaluated in a biennial experiment for their turf and forage characteristics. Selfing caused significant inbreeding depression for plant fresh and dry weight and leaf length and width in the first year for both EI and EF genotypes. In the second year, only leaf length remained depressed among these characters. Also, for the most growth, turf and reproductive traits, EI populations showed less depression. The presence of endophyte in self‐pollinated populations made an increasing effect for the number of seed per spike and days to heading, although seed weight was reduced. Some of the populations derived from self‐pollination and infected with fungal endophyte including S9 and S10 were even superior to the two commercial varieties in terms of both seed production and turf characteristics. However, for seed‐related characteristics including number of spikes per plant, seed weight and seed yield, EF populations including Speedy and Vigor were more reproductive than EI populations. It is concluded that selfing may increase the discrimination between EI and EF ryegrass plants because endophyte infection may mitigate the negative consequences of inbreeding depression in prone populations.

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Evidence for Heterosis in Italian Ryegrass (Lolium multiflorum Lam.) Based on Inbreeding Depression in F2 Generation Offspring from Biparental Crosses

Cited by 16 publications

References 30 publications

Extraordinary Heterosis Found In A Forage Grass Hybrid, Festuca apennina × F. pratensis

Extraordinary Heterosis Found In A Forage Grass Hybrid, Festuca apennina × F. pratensis

Genotype selection for physiological responses of drought tolerance using molecular markers in polycross hybrids of orchardgrass

A simultaneous effect of selfing and Epichloë endophyte on forage, seed yield and turf characteristics of perennial ryegrass (Lolium perenne L.)

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