Development of improved non-dormant alfalfa cultivars with high yield and increased persistence in Georgia and other target regions of the southeast

Summary

Development of non-dormant alfalfa cultivars adapted to the southeast, for growing as hay or interseeding in bermudagrass.

Situation

Alfalfa production in Georgia offers producers a significant profit potential through selling hay, or by grazing or conserving the surplus as haylage. Over several years, the breeding program devoted a sizable effort working with county extension agents establishing alfalfa demonstration plots in grower's fields and providing technical assistance in the management of alfalfa as a companion crop in bermudagrass pastures. An increasing number of bermudagrass growers across the southeast have started incorporating alfalfa into suppressed or closely clipped bermudagrass pastures. They harvest nearly pure alfalfa cuttings early in spring and later in fall, and by summer, their bermudagrass comes on strong. Most of these growers were attracted to alfalfa because they have seen enormous improvement in the quality of their hay (90 RFQ for bermudagrass hay vs. 170 for alfalfa-bemudagrass mixture) and they were able to save on the application of nitrogen fertilizer. The operation was a great success that attracted private seed companies like America's Alfalfa® who started their own demo program interseeding alfalfa in growers' bermudagrass fields across the southeast. Alfalfa cultivars Bulldog 505 and 805, developed at UGA, have proven so far to be the most persistent cultivars on the market for the southeast.

Response

We are pursuing several complementary approaches to develop elite alfalfa cultivars and implement a pipeline for continued development and release of alfalfa germplasm adapted to the southeast. 1. Incorporation of novel genetic diversity to broaden our alfalfa germplasm base and identify new parents adapted to Georgia edaphic and climatic conditions. Twenty-two genetically diverse populations were developed by crossing 42 selections based on 3 year testing of 226 accessions of germplasm of alfalfa introduced from various parts of the world at the JPC for yield and winter dormancy. These populations will undergo selection and evaluation for yield and persistence under grazing and eventually development of new cultivars. 2. Selection for low pH and Aluminum tolerance. The southeast of the US is characterized by low pH soils and high aluminum content. Even when lime is applied, the subsoil will remain acidic. 1200 surviving plants representing 448 PIs were dug from the field in Tifton and were transplanted in fall 2015 for yield evaluation at the JPC farm. These selections were made from 1,040 alfalfa accessions and cultivars from the US and various countries that were planted in 2013 at Tifton in a field of pH 4.8-5.2 to evaluate their performance in acid soils as well as identifying sources of aluminum tolerance. 3. Selection for persistence in Bermuda grass stands and grazing tolerance. Currently, we are testing six advanced experimental populations for regional performance and potential release as new cultivars, in addition to 17 populations being advanced at various stages of selection. 4. Incorporation of winter hardiness into non-dormant alfalfa germplasm.

Impact

We completed testing six advanced experimental populations for regional performance and potential release to growers, Two populations of dormancy 8 and 9 exceeded all the commercial check cultivars in performance as pure stand or in buermudagrass mixtures.These will add great values to options livestock producers have to improve their pastures and their income.

State Issue

Agricultural Profitability and Sustainability

Details

• Year: 2016
• Geographic Scope: Multi-State/Regional
• County: Oconee
• Program Areas:
  • Agriculture & Natural Resources