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United States Department of Agriculture

Agricultural Research Service

2009 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.

3.Progress Report
The program to develop pinkeye-type southernpea lines that exhibit yield potential equivalent to leading blackeye-type bean cultivars was continued; F2 seeds were harvested from F1 (California Blackeye No. 46 x Greenpack-DG) plants, the F2 seeds were evaluated for needed seed characteristics, and a large population of plants grown from the selected F2 seeds were evaluated in a field test for needed plant habit, yield, pod, and seed characteristics. Efforts were initiated to evaluate the 700-accession core of the USDA Cowpea Germplasm Collection for reaction to a local tomato strain of the Tomato spotted wilt virus. Efforts were continued to develop various types of open-pollinated Habanero- and sweet-type peppers that exhibit high levels of resistance to root-knot nematodes. The program to develop a yellow-fruited, Habanero-type pepper that is highly resistant to root-knot nematodes was completed; the advanced breeding line PA-560 is ready for release. A breeding program to develop a root-knot nematode resistant, pimento-type pepper was completed; the breeding line PA-570 is ready for release as a named cultivar. Efforts to incorporate a root-knot resistance gene into sweet banana, sweet cherry, and cubanella types of sweet pepper were continued. A program to develop F1 hybrids of Habanero-type peppers that are resistant to root-knot nematodes and multiple virus diseases and tolerant to heat stress was continued; 12 experimental hybrids were evaluated in field tests.

1. Release of the root-knot nematode resistant, red-fruited Habanero pepper PA-559. The increasing popularity of hot peppers in the United States has created intense interest in the Habanero, an extremely pungent type of pepper belonging to the domesticated Capsicum species C. chinense. Root-knot nematodes are major pests of Habanero peppers, and the ideal solution to this pest problem would be the use of resistant cultivars. About 14 years ago, efforts were initiated to transfer a root-knot nematode resistance gene from a Scotch Bonnet-type pepper into a red-fruited Habanero-type pepper. These efforts resulted 18 Sep 2008 release of the red-fruited, root-knot nematode resistant, advanced breeding line PA-559. PA-559 is recommended for use as a parental line by pepper breeders interested in developing root-knot nematode resistant cultivars of Habanero-type peppers. In light of the restrictions for continued use of methyl bromide to fumigate soils, the development of resistant cultivars is critical for continued production of Habanero-type peppers in areas where soils are infested by root-knot nematodes.

5.Significant Activities that Support Special Target Populations
A considerable portion of the resources of this project is directed towards the development of southernpea and pepper cultivars needed by small farmers and limited resource producers. Several of the southernpea and pepper cultivars under development are targeted for use by market gardeners.

6.Technology Transfer

Number of the New/Active MTAs (providing only)1

Review Publications
Fery, R.L. 2009. ‘ZipperCream-GC’, a Large-seeded, Cream-type Southernpea with a Green Cotyledon Phenotype. HortScience. 44(5):1474-1475.

Fery, R.L. 2009. ‘WhiteAcre-DG’, a Small-seeded, Cream-type Southernpea with an Enhanced Persistent Green Seed Phenotype. HortScience. 44(5):1472-1473.

Last Modified: 7/27/2016
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