Introgression of genes for cotton leaf curl virus resistance and increased fiber strength from Gossypium stocksii into upland cotton (G. hirsutum)

The current epidemic of cotton leaf curl disease (CLCuD) in Pakistan started in 1988 with the natural host range limited to a few plant species in the family Malvaceae. However, we have observed expansion in the host range of the virus, and several non-Malvaceous plants were found to be infected with the virus. Characteristic symptoms of CLCuD such as leaf curl and enations have been observed on radish plants, primarily in kitchen gardens. However, in 1999, levels of infection of 10 to 90% were observed both in commercial fields and kitchen gardens in the Punjab province of Pakistan. Both symptomatic and nonsymptomatic samples were collected from five different locations. Total DNA was isolated, dot-blotted on nylon membrane, and a full-length clone corresponding to DNA A of cotton leaf curl virus was labeled with 32P dCTP and used as a probe for the detection of a begomovirus. Strong signals were observed in symptomatic plants while no signals were observed in nonsymptomatic plants. Infection with a begomovirus was further confirmed by polymerase chain reaction (PCR) using degenerate primers for DNA A (1). Primers specific for the two distinct begomoviruses associated with CLCuD were also used in PCR reactions (2), and products of the expected size were obtained from all symptomatic samples, confirming infection with begomoviruses similar to those associated with CLCuD. A full-length probe of a nanovirus-like molecule associated with cotton leaf disease (3), called DNA 1 was labeled with 32P dCTP and detected the virus only in symptomatic plants. Similarly, primers specific for DNA 1 (3) amplified a product of expected size when used in PCR. On the basis of symptomatology and the detection of specific viral components associated with the disease, we confirmed that radish plants are infected with Cotton leaf curl virus (CLCuV). Since radish is a short duration crop, infection of CLCuV in radish may not serve as a direct source of infection for the next cotton crop. However, it is a potential threat to tomato crops which overlap with radish in the Punjab province. The detection of CLCuD in radish is another example of the mobilization of begomoviruses to previously unknown hosts. References: (1) M. R. Rojas et al. Plant Dis. 77:340, 1993. (2) S. Mansoor et al. Pak. J. Bot. 31:115, 1999. (3) Mansoor et al. Virology 259:190, 1999.

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Estimation of Genetic Effects Controlling Different Plant Traits in Cotton (Gossypium Hirsutum L.) Under Clcuv Epidemic Condition

Cercetari Agronomice in Moldova ◽

10.1515/cerce-2017-0004 ◽

2017 ◽

Vol 50 (1) ◽

pp. 47-56 ◽

Cited By ~ 1

Author(s):

A.M. Khan ◽

S. Fiaz ◽

I. Bashir ◽

S. Ali ◽

M. Afzal ◽

...

Keyword(s):

Plant Traits ◽

Fiber Strength ◽

Block Design ◽

Cotton Leaf ◽

Cotton Leaf Curl Virus ◽

Fiber Fineness ◽

Cotton Genotypes ◽

Seed Index ◽

Leaf Curl Virus ◽

Additive Genes

Abstract Nine cotton genotypes, comprised of four non Bt males (CIM-1100, CIM-506, FH-942 and FH-900), five Bt female genotypes (FH-113, FH-114, MNH- 886, AA-703 and IR-3701) and their 20 crosses were screened in order to evaluate their response to Cotton leaf curl virus symptoms through epidemiology in the field and greenhouse. The 20 crosses among their nine parents were sown in two replications under randomized complete block design, during 2013 and 2014. The mean squares were significant for all traits indicating that both additive and non-additive genes control the characters, but non-additive genes were more important because, variance of dominant genes were higher than additive genes. In our test, FH-900 showed the best performance against CLCuV, number of lobes per boll and seed yield. The CIM- 1100 genotype performed well in boll weight, fiber strength and fiber fineness, whereas CIM-506 was good for plant height, number of sympodial branches and ginning. Maximum boll number, seed index and fiber length were shown by FH-942. Among lines, MNH886, FH-113, IR-3701 and FH-114 exhibited the best general combination for many traits. Hence, parents were preferred for hybridization program to improve the majority of characters. Hybrids FH-113 × FH-942, MNH-886 × CIM-1100, MNH-886 × FH-942, IR-3701 × CIM-506, AA-703 × CIM-1100, FH-114 × FH-942, FH-114 × CIM-1100 and MNH-886 × FH- 900 was best in specific combinations for different traits, especially against CLCuV. The results indicated that to increase resistance against CLCuV, hybrids should be exploited to develop CLCuV resistance.

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