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Title: Meiotic and reproductive behavior of facultative apomictic BC/sub 1/ offspring derived from Pennisetum americanum-P. orientale interspecific hybrids

Abstract

This study reports on the chromosome numbers, meiotic behavior, method of reproduction and fertility of BC/sub 1/ progenies from Pennisetum americanum L. Leeke, pearl millet X P. orientale L.C. Rich. interspecific hybrids backcrossed to P. americanum. This information would be useful for future studies on transfer of genes controlling apomixis from the tertiary gene pool to P. americanum. Two facultatively apomictic interspecific hybrids between Pennisetum americanum, (A. chromosomes) and P. orientale (O chromosomes), 2n=25, were pollinated with P. americanum. Sixteen backcross progenies were obtained which were of three cytotypes: 32-(14 A + 18 O), 23-(14 A + 9 O), and 27-(7 A + 20 O) chromosomes. They resulted from fertilization of unreduced gametes or partially reduced gametes by a 7 A chromosome gamete, or by development or unreduced aposporic embryo sacs, respectively. In 23 chromosome plants, the 14 A chromosomes paired mainly as bivalents or remained as univalents while the 9 O chromosomes appeared as univalents. Intergenomal pairing between P. americanum and P. orientale also were observed and could make segmental exchange possible. In the 27 chromosome progeny, the 20 O chromosomes paired, while the 7 A chromosomes remained as univalents. Meiotic behavior in 32-chromosome plants was regular with 7more » A bivalents plus 9 O bivalents. The backcross progenies were male sterile but partially female fertile and produced a few seeds when pollinated with P. americanum pollen. The 23-chromosome, BC/sub 1/ progeny were reconstituted in BC/sub 2/ progenies of 32-chromosomes plants X pearl millet. All BC/sub 1/ had some degree of apomicitic embryo sac development and the 23-chromosome plants showed apomictic development even though the O chromosomes were in the simplex condition.« less

Authors:
;
Publication Date:
Research Org.:
Univ. of Georgia, Tifton
OSTI Identifier:
5745080
DOE Contract Number:
AS09-76EV00637
Resource Type:
Journal Article
Resource Relation:
Journal Name: Soil Sci. Soc. Am. J.; (United States); Journal Volume: 23:1
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; MILLET; HYBRIDIZATION; MEIOSIS; REPRODUCTION; CHROMOSOMES; FERTILITY; GAMETES; GENE RECOMBINATION; GENES; CELL DIVISION; CEREALS; GERM CELLS; GRAMINEAE; GRASS; PLANTS; 550400* - Genetics

Citation Formats

Dujardin, M., and Hanna, W.W. Meiotic and reproductive behavior of facultative apomictic BC/sub 1/ offspring derived from Pennisetum americanum-P. orientale interspecific hybrids. United States: N. p., 1983. Web.
Dujardin, M., & Hanna, W.W. Meiotic and reproductive behavior of facultative apomictic BC/sub 1/ offspring derived from Pennisetum americanum-P. orientale interspecific hybrids. United States.
Dujardin, M., and Hanna, W.W. 1983. "Meiotic and reproductive behavior of facultative apomictic BC/sub 1/ offspring derived from Pennisetum americanum-P. orientale interspecific hybrids". United States. doi:.
@article{osti_5745080,
title = {Meiotic and reproductive behavior of facultative apomictic BC/sub 1/ offspring derived from Pennisetum americanum-P. orientale interspecific hybrids},
author = {Dujardin, M. and Hanna, W.W.},
abstractNote = {This study reports on the chromosome numbers, meiotic behavior, method of reproduction and fertility of BC/sub 1/ progenies from Pennisetum americanum L. Leeke, pearl millet X P. orientale L.C. Rich. interspecific hybrids backcrossed to P. americanum. This information would be useful for future studies on transfer of genes controlling apomixis from the tertiary gene pool to P. americanum. Two facultatively apomictic interspecific hybrids between Pennisetum americanum, (A. chromosomes) and P. orientale (O chromosomes), 2n=25, were pollinated with P. americanum. Sixteen backcross progenies were obtained which were of three cytotypes: 32-(14 A + 18 O), 23-(14 A + 9 O), and 27-(7 A + 20 O) chromosomes. They resulted from fertilization of unreduced gametes or partially reduced gametes by a 7 A chromosome gamete, or by development or unreduced aposporic embryo sacs, respectively. In 23 chromosome plants, the 14 A chromosomes paired mainly as bivalents or remained as univalents while the 9 O chromosomes appeared as univalents. Intergenomal pairing between P. americanum and P. orientale also were observed and could make segmental exchange possible. In the 27 chromosome progeny, the 20 O chromosomes paired, while the 7 A chromosomes remained as univalents. Meiotic behavior in 32-chromosome plants was regular with 7 A bivalents plus 9 O bivalents. The backcross progenies were male sterile but partially female fertile and produced a few seeds when pollinated with P. americanum pollen. The 23-chromosome, BC/sub 1/ progeny were reconstituted in BC/sub 2/ progenies of 32-chromosomes plants X pearl millet. All BC/sub 1/ had some degree of apomicitic embryo sac development and the 23-chromosome plants showed apomictic development even though the O chromosomes were in the simplex condition.},
doi = {},
journal = {Soil Sci. Soc. Am. J.; (United States)},
number = ,
volume = 23:1,
place = {United States},
year = 1983,
month = 1
}
  • This study reports on the chromosome numbers, meiotic behavior, method of reproduction and fertility of BC/sub 1/ progenies from Pennisetum americanum L. Leeke, pearl millet x P. orientale L.C. Rich. interspecific hybrids backcrossed to P. americanum. Two facultatively apomictic interspecific hybrids between Pennisetum americanum, (A. chromosomes) and P. orientale (O chromosomes), 2n = 25, were pollinated with P. americanum. Sixteen backcross progenies were obtained which were of three cytotypes: 32-(14 A + 18 O), 23-(14 A + 9 O), and 27-(7 A + 20 O) chromosomes. They resulted from fertilization of unreduced gametes or partially reduce gametes by a 7more » A chromosome gamete, or by development or unreduced aposporic embryo sacs, respectively. In 23 chromosome plants, the 14 A chromosomes paired mainly as bivalents or remained as univalents while the 9 O chromosomes appeared as univalents. Intergenomal pairing between P. americanum and P. orientale also were observed and could make segmental exchange possible. In the 27 chromosome progeny, the 20 O chromosomes paired, while the 7 A chromosomes remained as univalents. Meiotic behavior in 32-chromosome plants was regular with 7 A bivalents plus 9 O bivalents. The backcross progenies were male sterile but partially female fertile and produced a few seeds when pollinated with P. americanum pollen. The 23-chromosome, BC/sub 1/ progeny were reconstituted in BC/sub 2/ progenies of 32-chromosome plants x pearl millet. All BC/sub 1/ progenies had some degree of apomictic embryo sac development.« less
  • Pearl millet, Pennisetum americanum (L.) Leeke, is an important world food and forage crop. Pennisetum orientale L.C. Rich. has genes for apomixis, perennial growth habit, pest resistance, and drought tolerance which could be used to improve pearl millet. The objectives of this research were to determine the cytotaxonomic relationship of these two species and to explore the feasibility of interspecific germplasm transfer. Five interspecific hybrids, 2n = 25, with 7 large P. americanum millet (A) and 18 small P. orientale (0) chromosomes were produced by pollinating cytoplasmic male sterile pearl millet with P. orientale pollen. Although the possibility of germplasmmore » exchange existed, the two species appeared to be not closely related. Among three hybrids examined, one was a facultative apomict, one was an obligate apomict and another was highly apomictic with 3% of ovules with sexual embryo sacs. Sixteen backcross progenies were established from interspecific hybrids pollinated with pearl millet pollen. The balanced chromosome number for both species in these latter plants should provide a mechanism for restoring fertility in the interspecific hybrid thus enabling germplasm transfer. The interspecific hybrids were male sterile but set about 1% seed when pollinated with pearl millet pollen.« less
  • Pearl millet, Pennisetum americanum (L.) Leeke, is an important world food and forage crop. Pennisetum orientale L. C. Rich. has genes for apomixis, perennial growth habit, pest resistance, and drought tolerance which could be used to improve pearl millet. The objectives of this research were to determine the cytotaxonomic relationship of these two species and to explore the feasibility of interspecific germplasm transfer. Five interspecific hybrids, 2n = 25, with 7 large P. americanum millet (A) and 18 small P. orientale (O) chromosomes were produced by pollinating cytoplasmic male sterile pearl millet with P. orientale pollen. The O chromosomes pairedmore » mainly as bivalents and the A chromosomes remained as univalents. A low frequency of AO chromosome associations were observed. Although the possibility of germplasm exchange existed, the two species appeared to be not closely related. Among three hybrids examined, one was a facultative apomict, one was an obligate apomict and another was highly apomictic with 3% of ovules with sexual embryo sacs. Sixteen backcross progenies were established from interspecific hybrids pollinated with pearl millet pollen. Seven plants were 2n = 23 with 14 A + 9 O chromosomes, five were 2n = 27 with 7 A + 20 O chromosomes and four were 2n = 32 with 14 A and 18 O chromosomes. The balanced chromosome number for both species in these latter plants should provide a mechanism for restoring fertility in the interspecific hybrid thus enabling germplasm transfer. The interspecific hybrids were male sterile but set about 1% seed when pollinated with pearl millet pollen.« less
  • The effects of polyploidy on 18 morphological and fertility characters were studied in six isogenic Pennisetum americanum (L.) Leeke x P. purpureum Schum, triploid (3x) and hexaploid (6x) clonal pairs. Four of the characters, inflorescence length and width, floret length, and flag leaf length increased in size for all clones with an increase in ploidy as a result of a dosage effect. Pollen diameter and stainability increased due to a more regular meiosis in the hexaploid (AAA'A'AB) compared to the triploid (AA'B) resulting in functional pollen grains. Differential responses to polyploidy among clones were observed for 12 plant characteristics: stomatalmore » length and frequency on both abaxial and adaxial surfaces, growth rate, tiller number per plant, plant height, stem thickness, days to flowering, flag leaf width, spikelet number per 5 cm inflorescence, and florets per spikelet. The different responses by clones are probably due to any one or combination of a dosage effect, gene number controlling a character, genotype of plant, and gene action and interaction both within and between the A and B genomes. This investigation showed the importance of studying a number of different genotypes when determining the effect of an increase in ploidy level on plant characters.« less
  • To determine the potential for germplasm exchange, interspecific hybrids form a cross between a pearl millet Pennisetum glaucum (L.) R. Br. {times} Pennisetum purpureum Schum. amphiploid crossed with a P. glaucum {times} Pennisetum squamulatum Fesen. interspecific hybrid were backcrossed four times to tetraploid pearl millet. The objective of this research was to determine the chromosomal characteristics of progeny obtained from pollinating both cytoplasmic-nuclear male sterile diploid (2n=14) and tetraploid (2n=28) pearl millet with near-tetraploid (2n=26 to 32) BC{sub 4} derivatives involving P. glaucum, P. purpureum, and P. squamulatum. Forty-five BC{sub 4} plants, 15 of which had chromosome numbers ranging frommore » 26 to 32, were used to pollinate cytoplasmic-nuclear male sterile diploid and tetraploid pearl millet, giving rise to 10 diploid and 70 near-tetraploid BC{sub 5} progeny, respectively. The recovery of diploid progeny suggest monoploid pollen was produced BC{sub 4} plants. All offspring expressed phenotypic traits of the male parent. Male fertility was restored completely in two diploid hybrids and restored partially in six near-tetraploid hybrids, probably because of the transfer of P. purpureum and/or P. squamulatum chromatin. Nine BC{sub 5} diploid offspring had 14 A and/or A{prime} genome chromosomes, which paired as seven bivalents at metaphase I. The near tetraploid BC{sub 5} offspring had from 27 to 30 chromosomes. Chromosome numbers observed in the young microspores of the BC{sub 4} plants ranges from n=1 to n=16. These results show that monoploid pollen can be produced from tetraploid or hexaploid hybrids and used for transferring gene(s) from wild relatives into pearl millet.« less