Anthracnose, leaf blight, and rust are important biotic constraints to grain and forage sorghum production worldwide and are best managed through host plant resistance. A sorghum mini-core collection, consisting of 242 germplasm accessions developed from a core collection of 2,246 landrace accessions originating from 58 countries, was evaluated to identify sources of resistance to foliar diseases. The mini-core accessions were evaluated in anthracnose- and leaf-blight-screening nurseries under artificial inoculation in the rainy and late rainy seasons, respectively, during 2009 and 2010. For rust resistance, screening was done under artificial inoculation in the greenhouse as well as in the field under natural infection. In all, 13 accessions were found resistant (score ≤3.0 on a 1-to-9 scale) to anthracnose and 27 to leaf blight in both 2009 and 2010. Six accessions exhibited resistance to rust in both the greenhouse and the field. In the resistant accessions, a wide range of diversity was observed for agronomic traits such as days to 50% flowering, plant height, and grain yield/plant, and morphological characteristics such as grain or glume color, glume coverage, endosperm texture, and panicle type (ear head compactness). Three mini-core accessions (IS 473, IS 23684, and IS 23521) exhibited resistance to all three diseases. These accessions with multiple disease resistance will be useful in sorghum disease resistance breeding programs.
Blast, also known as leaf spot, caused by Pyricularia grisea [teleomorph: Magnaporthe grisea], has emerged as a serious disease affecting both forage and grain production in pearl millet in India. Pathogenic variation was studied in a greenhouse using 25 M. grisea isolates collected from four major pearl millet growing states in India (Rajasthan, Haryana, Maharashtra and Uttar Pradesh) on ten pearl millet genotypes (ICMB 02444, ICMB 02777, ICMB 06444, ICMB 93333, ICMB 96666, ICMB 97222, ICMB 99444, 863B, ICMR 06222 and ICMB 95444). Differential reactions to the test isolates were recorded on ICMB 02444, ICMB 93333, ICMB 97222, 863B and ICMR 06222. The 25 isolates were grouped into five different pathotypes based on their reaction types (virulent = ≥ 4 score and avirulent ≤ 3 score on 1-9 scale). For the identification of resistance sources, a pearl millet mini-core comprising 238 accessions was evaluated under greenhouse conditions against five M. grisea isolates (Pg118, Pg119, Pg56, Pg53 and Pg45) representing the five pathotypes. Of 238 accessions, 32 were found to be resistant to at least one pathotype. Resistance to multiple pathotypes (2 or more) was recorded in several accessions, while three accessions (IP 7846, IP 11036 and IP 21187) exhibited resistance to four of the five pathotypes. Four early flowering (≤ 50 days) blast resistant mini-core accessions (IP 7846, IP 4291, IP 15256 and IP 22449) and four accessions (IP 5964, IP 11010, IP 13636 and IP 20577) having high scores (≥ 7) for grain and green fodder yield potential, and overall plant aspect were found to be promising for utilization in pearl millet improvement programs. Identification of five pathotypes of M. grisea and sources of resistance to these pathotypes will provide a foundation for breeding for blast resistance in pearl millet in India. Magnaporthe grisea (Herbert) Barr] has emerged as another serious disease in major pearl millet growing areas in India. This disease causes substantial yield losses of grain (23) and forage (29). Symptoms of the disease appear as gray, water-soaked foliar lesions that enlarge and become necrotic, resulting in extensive chlorosis and premature drying of young leaves (31). This disease becomes more severe during humid weather conditions especially with dense plant stands. Leaf blast on pearl millet has been found to be negatively correlated with green-plot yield, dry matter yield and digestive dry matter thus affecting the productivity and quality of the crop (29). ----------------------------------------------------------------------------------------------------------------In India, the disease was first reported from Kanpur, Uttar Pradesh (12). Although blast was considered a minor disease of pearl millet in India, the disease incidence has increased alarmingly during the recent years (1, 11). The blast pathogen infects several cereal crops, including rice, wheat, pearl millet, finger millet and foxtail millet, and several grasses. was still too large for replicated multiple evaluati...
Coconut mite (Aceria guerreronis 'Keifer') has become a major threat to Indian coconut (Coçcos nucifera L.) cultivators and the processing industry. Chemical and biological control measures have proved to be costly, ineffective, and ecologically undesirable. Planting mite-resistant coconut cultivars is the most effective method of preventing yield loss and should form a major component of any integrated pest management stratagem. Coconut genotypes, and mite-resistant and -susceptible accessions were collected from different parts of South India. Thirty-two simple sequence repeat (SSR) and 7 RAPD primers were used for molecular analyses. In single-marker analysis, 9 SSR and 4 RAPD markers associated with mite resistance were identified. In stepwise multiple regression analysis of SSRs, a combination of 6 markers showed 100% association with mite infestation. Stepwise multiple regression analysis for RAPD data revealed that a combination of 3 markers accounted for 83.86% of mite resistance in the selected materials. Combined stepwise multiple regression analysis of RAPD and SSR data showed that a combination of 5 markers explained 100% of the association with mite resistance in coconut. Markers associated with mite resistance are important in coconut breeding programs and will facilitate the selection of mite-resistant plants at an early stage as well as mother plants for breeding programs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.