Justification:
1. Variety and germplasm development.
Combining resistances to important pathogens, optimizing seed composition (high oleic oil), enhancing genetic diversity and improving abiotic stress (drought and heat) resistance will help enable public and private breeding programs to sustain improvement of resilient soybean varieties able to meet the production and quality of soybean products needed in the marketplace. Elite as well as potentially “good” diverse germplasm will be used as parents to develop new progeny to help bridge the gap in performance between exotic germplasm and elite varieties. High oleic, low linolenic soybean represents a value-added commodity. There is also a need to produce high-protein soybean meal, and increase the amount of soybean oil produced per acre to help meet the demand for soybean oil in such produces as biofuels. We will continue to incorporate these traits into KS adapted varieties. Resistance to SCN continues to be dominanted by the PI 88788 source in both public and private soybean varieties, despite the fact that HG Type 2 SCN populations, which reproduce well on this source of resistance, now dominate the North Central Region, including Kansas. Several recent releases by the KSU Soybean Breeding Program have utilized sources of resistance other than PI 88788 that have proven to be resistant to diverse HG Type 2 populations from across Kansas. Additionally, novel sources of resistance, including resistance gene stacks are being developed by soybean breeders, and these new resistances need to be incorporated into Kansas soybean germplasm to provide more durable resistance in the future.
2. Evaluate and implement breeding technologies.
Focusing on the development and use of new technologies will help improve genetic gain across public and private breeding programs. Advances in genomics have made genotyping cost effective, but robust models must be capable of predicting phenotypic performance. We are working with the soybean breeders and geneticists in the North Central US to test the effectiveness of recurrent selection of F1 progeny in soybean using genomic selection to predict progeny performance. This method has the potential to improve selection accuracy, reduce the time required to develop new varieties and increase the performance of the progeny relative to current breeding methods. Here we propose to further develop our genomic selection capabilities and combine traditional phenotypic selection with genomic selection and remote sensing to help develop robust genomic selection methods for soybean breeding based on Kansas environments and Kansas germplasm. Also, we will use and validate marker assisted selection to compliment phenotyping of traits such as Soybean Cyst Nematode resistance.
3. Drought and heat tolerance.
Soybean is perceived as a relatively drought and heat-tolerant crop. However, high temperatures and drought conditions during the seed-filling or seed development can dramatically reduce seed yield and modify seed composition. Therefore, maintaining soybean yield and a balanced seed composition under high temperature and drought stress is a major objective of the program with the long-term goal of helping to develop improved post-flowering drought and heat-stress resilient varieties and strengthen the improvement pipeline between untapped soybean germplasm and commercial soybean varieties. Development of soybean varieties and identifying stable and effective molecular markers available to the wider soybean community will help mitigate the negative impacts of drought and heat stress across major soybean growing regions of the US and elsewhere.
4. Breed transgenic events into elite breeding lines.
Field tests demonstrated lines expressing transgenes targeting nematode fitness decreased SCN cyst and egg numbers compared to non-transgenic controls. Breeding these lines with elite lines containing conventional sources of resistances would be important to determine if there is a synergistic effect by stacking resistance traits. Providing breeding programs with novel modes of resistance against both SCN and Fusarium virguliforme should help reduce the economic impact of these two organisms.
Procedures:
1. Variety and germplasm development.
Each year we will: hybridize selected parents in the fall and winter greenhouses, and summer growing seasons to produce progeny for this project; advance populations and lines lines for evaluation; plant and maintain field plots; collect agronomic, environmental, genomic and spatial data throughout the growing season; harvest plots in the fall; summarize and analyze data; plant and maintain fall and winter greenhouses and utilize winter nursery facilities to advance and increase populations and lines; and build training populations to discover new genes (markers), and optimize genomic and phenotypic selection models. Parents will be selected based on achieving the goals of producing progeny that will contribute to the genetic gain for soybean seed yield, increased genetic diversity in the US soybean gene pool, optimizing seed composition, and enhancing pest resistance and drought and heat tolerance. Breeding lines will be screened for resistance to multiple SCN populations representing the virulence diversity existing across Kansas. Throughout these breeding activities we will continue to stive to engage private breeders in collaborative activities to help them develop new materials for the farmer.
2. Develop, evaluate and implement breeding technologies.
We are currently testing a genomic selection model developed at the Univ. of Minnesota. This research involves developing lines and populations, build training sets and optimize models for Kansas growing conditions. Remote sensing technology will be combined with genomic selection to improve the speed and accuracy of identifying superior breeding material for both yield and seed composition.
3. Drought and heat tolerance.
We will evaluate commercial varieties and germplasm for response to drought and heat stress with a focus on seed yield and seed composition. Specific populations will be developed involving drought resistant parents to give rise to lines that will be evaluated in replicated field plots under dryland and irrigated conditions both in KS and regional trials. These efforts involve the discovery of new genes (markers) that can facilitate the incorporation on newly discovered genes into high-yielding backgrounds.
4. Transfer transgenic events into elite breeding lines.
For SCN resistant events, we will focus on incorporating transgenic traits into early MG4 lines with high yield potential from the KSU breeding program. Incorporating the transgenic traits into elite varieties with and without traditional sources of SCN resistance may help determine if there is any synergistic effect of multiple sources of SCN resistance. As events from the Dectes stem borer and the SDS resistance project are identified they will also be incorporated into appropriate elite varieties Presence of the transgene(s) in progeny will be determined using molecular markers. Lines will be rescreened for SCN resistance in greenhouse and field bioassays.