Marker assisted breeding for introgression of genetic male sterile ms10 gene from hot pepper to heat tolerant bell pepper
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Date
2020
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Punjab Agricultural University, Ludhiana-
Abstract
In the present investigation, marker assisted selection (MAS) strategy was employed to
introgress genetic male sterile (GMS) ms10 gene from the donor parent MS-12 (Capsicum
annuum var. annuum), popular GMS line, into the genetic background of eight heat tolerant
bell pepper (C. annuum var. grossum) inbreds, to develop new GMS lines in bell pepper. The
chi-square test (χ2) results of six F2 and BC1F2 populations showed that the ratio well fitted to
the Mendelian ratio i.e. 3:1, validated the non-discriminated segregation of the male sterility
(MS) trait possessing ms10 gene. The analysis confirmed that the MS trait is inherited by a
single recessive gene. Further, the recently identified molecular marker ‘AVRDC-PP12’
linked to the ms10 gene was employed to test the segregation in backcross generations of bell
pepper incorporated with the ms10 gene. A total of 576 and 360 individuals in BC1F1 and
BC2F1, respectively, 72 plants of each BC1 and 60 plants of each BC2 were screened
(foreground selection) for the ms10 gene by using SSR marker. Among the eight backcrossed
populations screened, six were showed compatibility with the ms10 gene. The results were
analyzed by χ2-tests to know whether the observed number of plants in each class fitted well
to the anticipated genetic ratio of 1:1. The molecular marker in each backcrossed series
displayed a good fit in-to the expected ratio of Mendelian segregation i.e. 1:1 for one gene in
backcross population(s), which was non-significant at a probability level of 0.05, indicating
the relationship with pepper male sterility ms10 gene. Simultaneously, targeted gene positive
(Ms10ms10) non-pungent (pun1) heterozygous plant(s) were identified in BC2F1 generations
using BF7 and BF9-SCAR marker. A total of 27 BC2F1 Ms10ms10 plants of MSSM-2
population were segregated in a 5: 22 non-pungent to pungent ratio, and 26 Ms10ms10 plants
of MSSM-3 segregated in 3 (non-pungent): 23 (pungent) ratio. The rest of the four BC2F1
populations, MSSM-1, MSSM-9, MSSM-17 and MSSM-21 have pungent heterozygous male
fertile (Ms10ms10 Pun1pun1) plant. The background recovery rate of the recurrent parent
phenome (RPP) in BC2F1 progeny was estimated by measuring the shift in means for
horticultural traits. Based on a paired 't' test analysis, out of six, the MSSM-1 and MSSM-2
generation was shown to be non-significant for all 19 studied traits followed by MSSM-3
(18), indicating a successful recovery of the recipient genome through marker-assisted
backcross breeding after successful introgression of the ms10 gene. Finally, from this work
six gene positive (ms10) GMS lines namely, MSSM-1, MSSM-2, MSSM-3, MSSM-9,
MSSM-17 and MSSM-21 were obtained. The newly developed GMS lines will provide great
economic value for non-pungent hybrid bell pepper seed production in the near future.
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Citation
Menisha Rani (2020). Marker assisted breeding for introgression of genetic male sterile ms10 gene from hot pepper to heat tolerant bell pepper (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.