2011 Annual Report
1a.Objectives (from AD-416)
Develop pinkeye-type southernpea (cowpea) lines that exhibit yield potential equivalent to leading blackeye-type bean cultivars. Identify host-plant resistance to emerging viral diseases (e.g., Tomato spotted wilt) in southernpea genetic resources and determine the genetic control of resistance. Develop open-pollinated advanced breeding lines of sweet peppers (Capsicum annuum) and Habanero-type peppers (C. chinense) highly resistant to root-knot nematodes. Develop Habanero-type F1 hybrid pepper cultivars which are tolerant to heat stress and highly resistant to Tomato spotted wilt virus, Pepper mottle virus, and root-knot nematodes.
1b.Approach (from AD-416)
The southernpea pinkeye-type cultivar GreenPack-DG and the high-yielding blackeye bean cultivar California Blackeye No. 46 will be used as the parental lines to initiate a plant breeding project with the major goal of breaking the apparent yield barrier in pinkeye-type southernpeas; the two cultivars will be crossed and pedigree and single-seed-descent breeding procedures will be employed to quickly advance progeny populations three generations per year (spring field cycle, fall field cycle, and a winter greenhouse cycle). Efforts to identify sources of resistance to Tomato spotted wilt virus (TSWV) in southernpea will involve the development of an efficient and effective methodology for evaluating germplasm and then the progressive evaluation of all available sources of resistance to other cowpea viruses, a collection of named southernpea and blackeye bean cultivars, and the 720 accession core of the USDA cowpea germplasm collection. If a source of TSWV resistance is identified, the methods of classical genetics will be employed to determine the genetic control of that resistance. A backcross breeding procedure will be used to incorporate a dominant root-knot nematode resistance gene into several non-bell, open-pollinated, sweet-type peppers; a similar approach will be used to incorporate a dominant resistance gene into open-pollinated Habanero-type peppers. An effort will be initiated to develop a series of candidate F1 hybrid Habanero-type cultivars that are resistant to root-knot nematodes and the major viral diseases and tolerant to heat stress. The USDA-developed, open-pollinated, Habanero-type cultivar TigerPaw-NR will be crossed with open-pollinated Habanero-type accessions from the Texas A&M University; TigerPaw-NR is a well adapted, high yielding cultivar that is homozygous for a dominant gene conditioning resistance to root-knot nematodes and the Texas accessions are homozygous for dominant genes conditioning resistance to Tomato spotted wilt and Pepper mottle viruses, compact plant habit, and the ability to set fruit during periods of high temperatures.
The program to develop pinkeye-type southernpea lines that exhibit yield potential equivalent to leading blackeye-type bean cultivars was continued; selections from a field-grown F5 population made during the summer of 2010 were advanced two generations off-season in the greenhouse using a single-seed-descent breeding scheme, and populations of F8 plants grown from the seeds harvested from the second greenhouse planting were evaluated in a replicated 2011 field test for needed plant habit, yield, pod, and seed characteristics. Efforts were continued to develop various types of open-pollinated, sweet-type peppers that exhibit high levels of resistance to root-knot nematodes. The third backcross in the breeding program to incorporate a dominate root-knot nematode resistance gene into a Red Cherry type of sweet pepper was completed; the second backcrosses in the programs to develop root-knot nematode resistant versions of Sweet Banana and Cubanelle types of sweet peppers were also completed. The breeding program to develop a high yielding, orange-fruited, Habanero-type, F1 hybrid pepper cultivar was completed.
To better utilize available resources at the U.S. Vegetable Laboratory and to strengthen priority research at this facility, this research project was terminated at the end of Fiscal Year 2011 and the appropriated money from it was redirected to other projects at the location.
Development of a high yielding, orange-fruited, Habanero-type, F1 hybrid pepper cultivar. Although cultivars belonging to the species Capsicum annuum account for most of the peppers grown in the United States, cultivars belonging to the species C. chinense are becoming increasingly popular. The Habanero-type pepper, a cultivar class belonging to C. chinense, is now quite common in the United States, but little work has been done by plant breeders to develop high-yielding, F1 hybrid cultivars. In 2008, researchers at the U.S. Vegetable Laboratory, Charleston, SC, and Texas A&M University, College Station, TX, initiated efforts to develop an early-maturing, high yielding, F1 hybrid cultivar utilizing parental lines developed by ARS-USDA and Texas A&M University. These efforts have resulted in the development of a new, high yielding, F1 hybrid. The most outstanding attribute of the new cultivar (Experimental Designation: PX-312) is its ability to produce high yields of large, attractive, orange-colored fruits, particularly high yields early in the season. The yield attributes of the new cultivar, particularly its potential for producing high early yields, should be especially appealing to farmers trying to widen their marketing window.
Fery, R.L., Thies, J.A. 2011. ‘Truhart-NR’, A Root-knot Nematode Resistant, Pimento-type Pepper. HortScience. 46(5):815-816.
Fery, R.L., Thies, J.A. 2011. PA-560, A Southern Root-knot Nematode Resistant, Yellow-fruited, Habanero-type Pepper. HortScience. 46(6):946-947.
Fery, R.L., Thies, J.A. 2011. PA-566, A Root-knot Nematode Resistant, Pimento-type Pepper. HortScience. 46(4):668-669.