NEW SOURCES OF RESISTANCE - CACAO GERMPLASM EVALUATION FOR NATURAL INCIDENCE OF WITCHES' BROOM

Fusarium wilt (caused by Fusarium oxysporum f. sp. lentis) is the most crucial limiting variable for decreasing yield levels of lentils (Lens culinaris Medik.) around the world. A set of 20 diverse lentil genotypes comprising breeding lines and released varieties was evaluated, along with susceptible controls, for resistance to fusarium wilt through natural incidence for two continuous years (2010–11 and 2011–12) in six diverse lentil-growing environments in India. Analysis of variance showed that the effect of genotype (G) and environment (E) for disease incidence was highly significant. Among the three sources of variation, the biggest contribution in disease occurrence was accounted for by environment (54.68%), followed by G × E interaction (17.32%). The high G × E variation necessitated assessment of the genotypes at different locations (environments). GGE biplot analysis of the studied genotypes revealed that genotype PL 101 and released cultivar L 4076 had low levels of disease incidence. The sources of resistance to fusarium wilt have great potential for use in lentil-breeding programs. Another biplot of relationships among environments demonstrated that, among the test locations, Sehore and Faizabad, were the most effective for differentiation of genotypes. On the basis of discriminating ability and representativeness, the Sehore location appeared an ideal testing site for natural incidence of F. oxysporum f. sp. lentis.

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Fuentes de resistencia a la antracnosis y la mancha angular en frijol común para Costa Rica.

Agronomía Mesoamericana ◽

10.15517/am.v11i1.17328 ◽

2006 ◽

Vol 11 (1) ◽

pp. 11

Author(s):

Rodolfo Araya ◽

Floribeth Mora ◽

Shree P. Shingh

Keyword(s):

Costa Rica ◽

Leaf Spot ◽

Angular Leaf Spot ◽

Disease Score ◽

Sources Of Resistance ◽

Breeding Lines ◽

Resistant Disease ◽

La Mancha ◽

Abiotic And Biotic Factors ◽

Natural Incidence

The objective of this study was to select sources of resistance to angular leaf spot and anthracnose from a diverse group of germplasm with known resistance to these diseases and other abiotic and biotic factors. Atotal of 173 common beans that included 46 landraces and 127 breeding lines were evaluated at two locations (Estación Experimental Fabio Baudrit Moreno and Sub-Estación Experimental Fraijanes, both of Universidad de Costa Rica) in 1996 and 1997. A mixture of four races (races 9, 10, 547, and 1024 of maximum virulence and coverage in Costa Rica) of the anthracnose pathogen was used to inoculate four times. Because of high natural incidence of angular leaf spot, inoculation was not necessary. Twenty-one landraces and 13 breeding lines were resistant (disease score of 3 or less) to antracnose. Only five landraces (G 12529, G 14934, G 19428, G 19696, and G 19831), one improved cultivar (ICA Tundama), and a breeding line UCR 55 had intermediate reaction (disease score between 4 and 6). Thus, for angular leaf spot evaluation of a much broader range of germplasm of common bean and other related species is suggested.

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New sources of resistance to hazardous organisms in pea in the eastern forest steppe of Ukraine

Plant Breeding and Seed Production ◽

10.30835/2413-7510.2014.42054 ◽

2014 ◽

Vol 0 (105) ◽

pp. 70-76

Author(s):

Т. В. Сокол

Keyword(s):

Forest Steppe ◽

Sources Of Resistance

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RESISTANCE TO MILDEW OF SELECTION FAMILY OF RED CURRANT THE BELAYA POTAPENKO × № 1426-21-80

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2020/4/38-40 ◽

1970 ◽

pp. 38-40

Author(s):

O. O. Kalinina ◽

O. D. Golyaeva ◽

O. V. Panfilova ◽

А. V. Pikunova

Keyword(s):

Powdery Mildew ◽

Field Resistance ◽

Disease Development ◽

Artificial Infection ◽

Sources Of Resistance ◽

Climate Conditions ◽

High Productivity ◽

Local Soil ◽

The Family ◽

Red Currant

Powdery mildew is one of the most harmful fungal diseases that causes economically significant damage to berry plantations. The disease is common in all areas of currant cultivation in the Russian Federation. In this regard, in modern conditions of intensive berry growing, the problem of breeding cultivars that are highly resistant to diseases and pests becomes urgent. Breeders have a difficult task to combine the adaptive potential of the cultivar with its annual high productivity and resistance to biotic environmental factors. When studying the adaptability of introduced cultivars of red currant and selected forms of the Institute to local soil and climate conditions, the following cultivars were identified as sources of economic and useful characteristics and involved in selection: ‘Belaya Potapenko’ as a complex source of resistance powdery mildew and high marketable and taste qualities of berries; SS 1426-21-80 as a source of high productivity and long racemes (raceme length 11-13 cm; up to 20 berries in the raceme). On their base the selection family of red currant has been developed: Belaya Potapenko × ♂SS 1426-21-80. The study of data on the destruction of hybrid seedlings of the selection family by powdery mildew showed that in epiphytotic conditions, the percentage of intensity of the disease development varies over the periods of screening from 0.2% in May to 20.4% in June. Such indicators served as a prerequisite for conducting a comparative test of breeding material in the field under artificial infection with powdery mildew. After artificial infection on the background of epiphytosis, the rate of intensity of the disease development increased slightly and amounted to 35.6% for the family. There were 30 highly resistant seedlings in the family, 10 of which have remained stable and highly resistant since 2018. In these plants we can assume the presence of the so-called field resistance, controlled by polygens, each of which does not give a visible effect of stability, but with different combinations determines one or another of its degree. Highly resistant seedlings will be used in further breeding studies to identify new sources of resistance to powdery mildew.

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Resistance to Lettuce Infectious Yellows Virus in Melon

HortScience ◽

10.21273/hortsci.33.3.534b ◽

1998 ◽

Vol 33 (3) ◽

pp. 534b-534

Author(s):

James D. McCreight

Keyword(s):

Cucumis Melo ◽

Dominant Gene ◽

Field Tests ◽

Single Dominant Gene ◽

Limited Data ◽

Sweetpotato Whitefly ◽

Sources Of Resistance ◽

Lettuce Infectious Yellows Virus ◽

Greenhouse Tests

Yellowing of melon (Cucumis melo L.) incited by lettuce infectious yellows virus (LIYV) reduces yield and fruit quality of infected plants. LIYV is transmitted only by the sweetpotato whitefly (Bemisia tabaci Genn.). Two naturally infected field tests indicated several potential sources of resistance to LIYV. PI 124112 and `Snake Melon' had mild symptoms in both field tests whereas PI 313970 was asymptomatic in the test in which it was included. In greenhouse tests using controlled inoculation, PI 313970 was asymptomatic, had negative ELISA assays for LIYV, and was negative for LIYV in serial transfers to Chenopodium. `Top Mark' and `PMR 5' were symptomatic, had positive ELISA assays for LIYV, and were positive for LIYV in serial transfers to Chenopodium in these greenhouse tests. Limited data indicate that resistance in PI 313970 is conditioned by a single, dominant gene.

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