Recipient Organization
ALCORN STATE UNIVERSITY
(N/A)
ALCORN STATE,MS 39096
Performing Department
Agriculture
Non Technical Summary
Melon breeders routinely use morphological markers for selection such as presence of orange flesh to improve β-carotene in melon (linked to flesh). Traits like seed germination, seedling vigor, fruit yield, early maturity, fruit size and sugar content are manifested by complex inheritance represented by multiple genes. Improvement in quantitative traits using traditional strategies is time consuming. For example, selecting for higher carotenoid concentration is difficult using visual appearance as was done in the past. Further, morphological markers will have an intrinsic disadvantage if the trait is influenced by the environment. CPW and FW are good examples of the devastating diseases, where developing new cultivars with resistance has thus far proven difficult in all the cucurbit crops, and has been indentured by producers as the major problems needing identification of linked markers for resistant alleles and further marker assisted selection to pyramid genes into cultivars. Development of disease and pest-resistant, high-quality melon varieties is critical to the economic prosperity of US melon farmers. Most importantly, our project activities include comprehensive demonstrations of the fruit quality traits, taste and flavor of the new introgressed morphotypes to the growers and consumers in four states in an effort to involve them to satisfy their requirements for good flavor, fruit quality, and high market value and address any concerns related to production. The major effort in this thrust will be conducting on-farm trials for participatory breeding to identify superior melon types to local cultivars. Selections for superior types will be made from participatory breeding at the farms of underserved communities. Farmers will be educated on how to harvest, store, and market the crop for fresh consumption. Farmers will also be taught how to save their seed for future production. During the field days, surveys will be conducted to elicit consumer preferences for fruit attributes (including shape, size, skin color and pattern, flesh color and texture, sweetness, flavor and aroma). On-line leaflets will be created for all appropriate new material that is created in the project. These will support the webinars, videos, and field days. One series of leaflets will be directed to the production, post-harvest handling, and marketing of cucurbits. An undergraduate internship program will be organized with cooperating scientists on the project.
Animal Health Component
30%
Research Effort Categories
Basic
40%
Applied
30%
Developmental
30%
Goals / Objectives
Melons (Cucumis melo L.) are a diverse group of cucurbits that includes the orange flesh cantaloupes, the green flesh honeydew, and the mixed melons (Casaba, Crenshaw, Persian, Santa Claus, and Juan Canari). The primary goal of our melon program is to use genomic assisted characterization of exotic melons for fruit traits and breeding of superior melon types by pyramiding favorable allele combinations into the US melons. We made a nested association mapping population (NAM) to maximize recombination from diverse world melon collections with the aim to carry out association mapping for improvement of fruit yield and quality traits. The ultimate goal of this three year project is the development of high-yielding, disease resistant melon varieties with improved fruit quality by selective crosses with exotic melon types in conjunction with molecular-based gene-introgression tracking methodologies. To address these challenges, we have assembled a team of inter institutional researchers involving breeders, horticulturists and geneticists to function at various levels of the project. The current proposal will address the need to integrate modern technologies that can create a set of common tools for marker assisted breeding through the specific objectives are 1) Development of high-throughput DNA marker platforms for melon by application of genotyping technologies to resolve public domain melon SNPs, 2) Evaluation of fruit yield, quality and resistance traits, 3) Association mapping for location of QTLs/Markers of importance, 4) Initiating marker-assisted breeding for improved traits, 5) ECO-TILLING of new alleles for genes of importance using GenBank resources and other publicly available candidate nutraceutical genes as well as publically available resistance and quality traits, and 6) Integration into a platform that facilitates data capture, storage and mining relevant to marker assisted breeding process. The combination of SNP polymorphism data over a range of morphotypes will allow us to identify functional marker panel consisting a set of highly informative markers for marker-assisted selection experiments in melons. This resource will facilitate the selection of novel traits for the introgression of exotic germplasm into elite backgrounds. We will develop simple horticultural procedures to maintain breeding lines, seed production, taste and flavor panels and cost-effective genomic protocols such as SNP genotyping and DNA diagnostics for melon trait identification. A program of exchange visits of students, scientists and extension personnel will efficiently allow technology and material transfer between the institutions. Resources will include a series of webinars to provide interactive education about the breeding efforts; a series of YouTube videos to describe the breeding lines, breeding techniques, and production methods; on-line leaflets on production, post-harvest handling, and marketing of cucurbits; and a "match the scientist to the student" undergraduate internship program. Demonstration plots of the advanced breeding lines, field days, and taste tests will allow farmers and consumers to be directly engaged in the project.
Project Methods
Genotyping: The proposal is cost effective as a large number of SNPs is available for public use. Currently there are 10387 SNPs available for public use on the Cucurbit Genomic Resource site (http://www.icugi.org/) that are identified from the aligned sequences of unigenes/DNA/BAC end of reference melon collections (Piel de Sapo, Vedrantais, PI161375, Dulce, agrestis and cantaloupe). Many new marker technologies are currently available for genotyping using SNPs, reflecting the increasing popularity of these markers. Once association mapping is carried out using a 200 DNA panel to identify QTLs, the selected SNPs can be further assayed for marker assisted selection or any targeted region genotyping or fine-mapping with Custom Infinium DNA Analysis products. Evaluation of fruit yield, quality and resistance traits: A set of NAM lines will be selected based on the screens from the existing DNA marker panels and superior NAM lines will be used for the participatory selection program. The lines identified at on-farm location studies from the two states (MS and WV) will be further screened for disease resistance for powdery mildew (PM) and (F.o.m) Fusarium oxysporum f. sp melonis at ASU to identify resistant lines. During the summers of 2013, 2014 and 2015, field tests will be run to measure various traits in the individual advanced progeny lines and morphotypes collections. Fruit yield/quality traits to be measured are Days to first flower, Days to first fruit maturity, fruit weight, fruit shape, fruit length, fruit width, thickness of pericarp, flesh color, fruit flavor, juiciness of flesh, sugar content, fruit number per plant, average fruit weight, number of lateral branches, exocarp and endocarp pressure (transportability) and shelf life (number of days in storage after harvest). Association mapping for location of QTLs/Markers of importance: Resolution of population structure is the most important activity before we undertake association mapping. Since this proposal aims to use all the world collections for association mapping, we propose to conduct analysis for population structure using the large genotyping data sets. Association mapping analysis will be conducted using the freely useable software TASSEL 2.1 (www.maizegenetics.net). Marker assisted selection (MAS) to identify lines with QTLs and pyramiding favorable alleles using recurrent selection We have identified markers linked to various fruit yield, quality and resistance traits using association mapping. Information on more QTLs, gene specific markers and NAM progenies that are homozygous for various important loci will be available from the association mapping activity. We propose to launch MAS in the first year itself using the markers that are already available from previous research. By the end of summer 2013, we will have our first MAS selected early generation progenies ready to test in the on farm trials. Our main focus will be to eliminate progenies that are heterozygous at favorable marker locus and forward homozygotes for contributing allele of marker. MAS allows the transfer of genes from a donor into an elite recipient genotype, the recurrent parent