Evaluate and select clonal propagated alfalfa and sainfoin plants under competition against grasses or alfalfa at Saskatoon and Lethbridge to develop new populations with improved persistence in a mixed stand and wider adaptability.
Persistence of alfalfa under grass competition or persistence of sainfoin under alfalfa competition raises a similar breeding question. This project was a 5-yr forage breeding research initiated in spring of 2017. The objectives of the research were: to evaluate and select 1) alfalfa clones growing in grass stands, 2) sainfoin clones growing in alfalfa stands at Saskatoon SK and Lethbridge AB, Canada, and 3) evaluate forage yield and quality of new breeding lines of alfalfa and sainfoin at the two locations in alfalfa- meadow brome or alfalfa-sainfoin mixtures.
We have propagated 1800 clones for 100 selected alfalfa genotypes and another 1800 clones for 100 selected sainfoin genotypes using stem cutting technique. In 2017, the alfalfa clones were transplanted to the newly seeded ‘Armada’ meadow bromegrass stand, and the sainfoin clones were transplanted into the seeded ‘Beaver’ alfalfa stand using a randomized complete block design with three replications. In 2018 and 2019, data were collected for plant height, spring growth, winter survival, hay yield (first cut yield), and regrowth yield at the two field locations. Forage nutritive value (crude protein, acid detergent fiber, and neutral detergent fiber) was also determined. Meadow brome provided extremely high competition to the alfalfa genotypes, which resulted in alfalfa yield reduction, and caused low survival rate. Similarly, seeded alfalfa stand became competitive for the transplanted sainfoin seedlings. This level of biotic stress was expected. Significant variations in plant height, spring vigor, dry matter yield and forage nutritive value were observed for both species. In the AMMI analysis of variance, the environmental effect explained 33.7% (alfalfa) and 54.8% (sainfoin) of variation for the total dry matter yield. Among the measured traits, plant height was a higher heritable trait with broad sense heritability of 0.16 (alfalfa) and 0.18 (sainfoin). The biplot Y x Weighted Average of Absolute Scores from the singular value decomposition of the matrix of BLUPs stability index (WAASB) identified several promising genotypes with superior performance and stability across different environments. Based on the performance data from the two sites over two years, superior genotypes of alfalfa and sainfoin were selected for new population development.
Two alfalfa breeding populations (SL910AF and SL911AF) two new sainfoin poulations (SL912SF and SL913SF) were developed based on above mentioned data collection and analysis. The new alfalfa population was seeded with meadow brome, and new sainfoin was tested in alfalfa-sainfoin mixtures. Although there was significantly better performance of alfalfa line SL911AF at the Clavet site, but it was not evident in Lethbridge. Sainfoin new line SL912SF showed significant advanrage at both sites when it was growing with sainfoin-alfalfa mixture.
Although our approach was effective, development of clones, and data collection from mixed stand required more labour and high cost compared to a standard spaced nursery evaluation. This clonal method may be more effective if it is supported by genomic selection.
- Sainfoin new line SL912SF showed significant improvement over check cultivars, which will be further tested for potential release as a variety for alfalfa-sainfoin mixed stand seeding.
- Moden plant breeding should apply methods such as WAASB to detect best genotypes for new population development across different environments.
- Plant selection under species competition tends to increase plant height.
- Sainfoin tends to respond more to clonal plant selection than the alfalfa.