Inheritance Of Fertility Restoration Research Articles

Inheritance of fertility restoration of A4 cytoplasm in pearl millet [Pennisetum glaucum (L.) R. Br.

Present investigation was carried out to study the mode of inheritance of fertility restoration for A4 cytoplasm using pollen fertility and seed set per cent as criterion in determining the fertile and sterile plants. Two CMS lines of A4 cytoplasm were crossed with two fertility restorers generating four F1 crosses, namely, ICMA 99111 x PPMI 1003, ICMA 99111 x PPMI 1087, ICMA 03999 x PPMI 1003 and ICMA 03999 x PPMI 1087, their F2s and backcross generations. All the F1s were completely fertile indicating complete fertility restoration. F2s and backcross generations were evaluated at IARI, New Delhi and IARI Regional Centre, Dharwad during summer 2017 and χ 2 test was applied to test the significance. At both the locations, all the F2 segregating populations fit well into a Mendelian ratio of 15:1 indicating digenic duplicate dominance of fertility restoring genes with χ 2 value of 0.82, 2.90, 0.04, 3.97, 4.86, 4.98, 0.02, 1.26, 3.15, 4.98, 3.15 and 0.02. The F2 hypothesis was verified with the observed frequency of segregating plants fitting well into 3:1 ration with χ 2 value of 5.45, 1.93, 4.93, 0.60, 2.83, 0.44, 4.94, 2.77, 3.33, 0.13, 4.08 and 1.51. It is further confirmation of the findings that fertility restoration is indeed governed by two duplicate genes. Association between pollen fertility and seed set per cent was significant and positive.

Inheritance of fertility restoration involving id type cytoplasmic male sterility system in rice (Oryza sativa L.) using ten different restorer lines

Inheritance of fertility restoration was studied in crosses involving ten elite restorer lines of rice viz. BR827R, BR168R, BR6723-1-1-2R, M.H.63R, M.H.77R, Gui99R, IR40750R, IR64R, AjayaR and IR44675R and one male sterile line II32A with ID (Indonesian paddy type) sources of cytoplasmic male sterility. The segregation pattern for pollen fertility of F2 and BC1 populations of crosses involving II32A indicated the presence of two independent dominant fertility restoring genes. The mode of action of the two genes varied in different crosses revealing three types of interaction, i.e. epistasis with dominant gene action, epistasis with recessive gene action, and epistasis with incomplete dominance.SAARC J. Agri., 13(1): 207-215 (2015)

Complete mitochondrial genome sequence and identification of a candidate gene responsible for cytoplasmic male sterility in radish (Raphanus sativus L.) containing DCGMS cytoplasm

A novel cytoplasmic male sterility (CMS) conferred by Dongbu cytoplasmic and genic male-sterility (DCGMS) cytoplasm and its restorer-of-fertility gene (Rfd1) was previously reported in radish (Raphanus sativus L.). Its inheritance of fertility restoration and profiles of mitochondrial DNA (mtDNA)-based molecular markers were reported to be different from those of Ogura CMS, the first reported CMS in radish. The complete mitochondrial genome sequence (239,186bp; GenBank accession No. KC193578) of DCGMS mitotype is reported in this study. Thirty-four protein-coding genes and three ribosomal RNA genes were identified. Comparative analysis of a mitochondrial genome sequence of DCGMS and previously reported complete sequences of normal and Ogura CMS mitotypes revealed various recombined structures of seventeen syntenic sequence blocks. Short-repeat sequences were identified in almost all junctions between syntenic sequence blocks. Phylogenetic analysis of three radish mitotypes showed that DCGMS was more closely related to the normal mitotype than to the Ogura mitotype. A single 1,551-bp unique region was identified in DCGMS mtDNA sequences and a novel chimeric gene, designated orf463, consisting of 128-bp partial sequences of cox1 gene and 1,261-bp unidentified sequences were found in the unique region. No other genes with a chimeric structure, a major feature of most characterized CMS-associated genes in other plant species, were found in rearranged junctions of syntenic sequence blocks. Like other known CMS-associated mitochondrial genes, the predicted gene product of orf463 contained 12 transmembrane domains. Thus, this gene product might be integrated into the mitochondrial membrane. In total, the results indicate that orf463 is likely to be a casual factor for CMS induction in radish containing the DCGMS cytoplasm.

INHERITANCE OF FERTILITY RESTORATION INVOLVING WILD ABORTIVE CYTOPLASMIC MALE STERILITY SYSTEM IN RICE (Oryza sativa L.)

Inheritance of fertility restoration was studied in crosses involving ten elite restorer lines of rice viz. BR6839-41-5-1R, BR7013-62-1-1R, BR7011-37-1-2R, BR10R, BR11R, BR12R, BR13R, BR14R, BR15R and BR16R and one male sterile line Jin23A with WA sources of cytoplasmic male sterility. The segregation pattern for pollen fertility of F2 and BC1 populations of crosses involving Jin23A indicated the presence of two independent dominant fertility restoring genes. The mode of action of the two genes varied in different crosses revealing three types of interaction, i.e. epistasis with dominant gene action, epistasis with recessive gene action, and epistasis with incomplete dominance.DOI: http://dx.doi.org/10.3329/bjpbg.v24i1.16997

Genetics of Fertility Restoration in A4‐Based, Diverse Maturing Hybrids of Pigeonpea [Cajanus cajan (L.) Millsp.

ABSTRACTRecently, a breeding technology for hybrid pigeonpea [Cajanus cajan (L.) Millsp.] based on cytoplasmic‐nuclear male sterility (CMS) and partial natural outcrossing was developed at ICRISAT. The limited number of experimental hybrids tested has shown the presence of a considerable amount of hybrid vigor for seed yield. In the present study, one extra‐early‐ (120 d), two early‐ (150 d), and two late‐maturing (180 d) pigeonpea hybrids were studied to generate information on the genetics of fertility restoration of the A4 CMS system. In the extra‐early‐maturing hybrids, pollen fertility was controlled by a single dominant gene, whereas in the early‐ and late‐ maturing hybrids, male fertility was governed by two duplicate dominant genes. It was also observed that hybrids with two dominant genes produced a greater pollen load and expressed greater stability as compared with those carrying a single dominant gene. The information on the inheritance of fertility restoration will help in designing strategies for breeding elite hybrid parents, and it was concluded that for breeding hybrids with stable fertility restoration, the presence of two dominant genes is essential.

Genetic analysis of fertility restoration genes for WA-type cytoplasmic male sterility in Iranian restorer rice line DN-33-18.

Cytoplasmic genetic male sterility system can be used to exploit heterosis in grain crops only when the effective restorer lines are available. Crosses between an Iranian CMS line Neda A with three newly developed lines DN-33-1, DN-33-18 and DN-32-6 showed that only the cross of Neda-A/DN-33-18 had more than 80% pollen and grain fertility in F1 generation. The inheritance of fertility restoration in F 2 population of this cross was evaluated at flowering and grain filling stages. Pollen staining test with 1% I 2 KI solution showed segregation ratio of 15:1 (fertile: sterile), representing two nuclear independent dominant genes controlling the trait carried by fertile parent DN-33-18. Segregation for spikelet fertility in F 2 confirmed the results of pollen fertility test. Molecular tagging of fertility restorer genes with SSR markers showed that four markers RM258, RM171, RM591 and RM3148 produced polymorphic bands between two parents. Linkage analysis on F 2 recessive class showed that RM258 and RM171 (on chromosome 10) flanked to restorer gene Rf4 at the distances of 3.1 and 6.3 cm, respectively. In this study polymorphism was not detected for Rf3 gene using SSR markers RM1, RM443, RM315 and RM294 on chromosome 1 of rice but we found new SSR marker RM3148 linked with Rf locus at a genetic distance of 19.7 cm. Key words : Rice, cytoplasmic male sterility (CMS), inheritance, molecular tagging, simple sequence repeat (SSR) markers.

Molecular tagging of the male fertility restorer gene for the 501-8S cytoplasmic male sterility in rapeseed (Brassica napus L.)

The cytoplasmic male sterile (CMS) system has been successfully used to explore heterosis in rapeseed (Brassica napus L.). A newly developed male sterile line (501-8S) was characterised for its male fertility response to temperature and photoperiod, and the inheritance of fertility restoration. Segregation analysis using F1 and F2, BC1, and F3 populations of the crosses between the 501-8S and fertile lines of B. napus revealed that fertility restoration was conferred by a dominant nuclear gene (Rf). The F2 population of the cross 501-8S × Yuyou1 was used as a mapping population to map the Rf gene. A combination of bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) methodology was used to identify putative markers linked to the Rf gene. Twenty-nine of the 1280 primer combinations tested revealed polymorphism between the 2 extreme bulks. Further testing of these primer combinations in individual plants identified 5 AFLP markers tightly linked to the Rf gene with a map distance of less than 5.0 cM. All 5 markers were on one side of the restoration gene in the coupling phase. The closest marker, EA02MG03-260, is only 0.4 cM from the Rf gene. The EA02MG03-260 marker was converted to a dominant sequence characterised amplified region (SCAR) marker (SCARE2M3-214). Amplification using this locus-specific primer generated specific bands with male fertile plants when tested using the mapping population. Specific amplification of SCARE2M3-214 was also detected in all 3 male sterile plants and their F1 hybrids, with 5 restorer lines used for verification. Thus, SCARE2M3-214 will be very useful for the development of new restorer lines by the transfer of the Rf gene into other breeding lines. It can also be used for isolating the Rf gene by means of map-based cloning.

Genetic and epigenetic regulation of male fertility restoration in the 9E, A4 and M35 CMS-inducing cytoplasms of sorghum

The use of new CMS-inducing cytoplasms significantly increases the genetic variability of cultivated sorghum hybrids. The aim of the research was to study the inheritance of fertility restoration in new types of male-sterile cytoplasms (A4, 9E, M35) and to explore the reasons for its instability. Genetic analysis revealed that the restoration of male fertility was controlled by dominant genes, whose expression was strongly dependent on a sufficient level of water availability to plants during anther and pollen formation. An epigenetic mechanism for “switching on” fertility-restoring gene expression in F1 hybrids is proposed, which is regulated by water availability to plants. This “active” state of fertility-restoring genes is stably expressed in self-pollinated progenies of restored hybrids, irrespective of their water availability conditions, but is not transmitted to testcross hybrids grown under arid conditions.

Inheritance of Pollen Fertility Restoration in Cytoplasmic Male‐Sterile Upland Cotton1

Information regarding the inheritance of fertility restoration in cytoplasmic male‐sterile cotton will be a valuable tool in commercial production of F1 hybrid cotton seed. F1, F2, and testcross populations were planted in 1975 at two locations to determine the inheritance of the fertility‐restoring factor in cytoplasmic male‐sterile Upland cotton (Gossypium hirsutum L.). Fertility restoration in cytoplasmic male‐sterile cotton is controlled by a single gene probably expressing partial dominance. Either some of the F2 plants were misclassifled or some minor modifying factor(s) was slightly deleterious to the growth and development of fertile plants in segregating populations. G. barbadense L. apparently has a factor that enhances pollen production in the F1 hybrid. A breeding program is underway to transfer this factor(s) into Upland stocks. Fertile plants in segregating F2 populations showed a significantly higher lint percentage than corresponding sterile plants. Higher micronaire was found for sterile plants than fertile plants.

Fertility Restoration of Male‐Sterile Cytoplasm in Wild Sunflowers1

Wild sunflower (Helianthus spp.) populations, collected from the northern Great Plains, were evaluated in crosses with a cytoplasmic male‐sterile inbred line to determine the frequency of fertility restorer genes in wild annual species and obtain information on the inheritance of fertility restoration. All of 52 H. annuus L. and six of seven H. petiolaris Nutt. populations were found to possess dominant genes for fertility restoration. Segregation ratios of male‐fertile to male‐sterile plants in the BC1 and F2 generations of seven crosses suggested that four genes were involved, and that fertility was restored when at least two dominant alleles were present at any of the four loci. Segregation occurred for one gene in four crosses, three genes in two crosses, and possibly four genes in one cross. Although the wild sunflower populations used in this study cannot be used directly as restorers in commercial production of hybrids, lines with acceptable agronomic characteristics were identified after one and two backcrosses to cultivated types.

Chromosomal Location of Male Fertility Restoring Genes in Six Lines of Common Wheat1

A monosomic set of male‐sterile ‘Chris’ (Triticum aestivum L.) with T. timopheevi Zhuk. cytoplasm was used to determine the chromosomal location of Rf‐genes in six male fertility restoring lines (FR‐lines) of T. aestivum L. The six FR‐lines were: R1‐Lee (Nebraska 542437/T. aestivum ‘Lee’), R2‐Sonora 64 (T. timopheevi/2*T. aestivum ‘Marquis’//‘Sonora 64’), R3 (T. timopheevi/3*T. aestivum ‘Marquis’), R4 (amphidiploid T. timopheevi‐Ae. squarrosa/3*T. aestivum ‘Dirk’), R5 (T. Zhukovsky Men. and Er.,/3*T. aestivum ‘Justin’), and T. aestivum ‘Primepi’. The relative proportions of male‐sterile and male‐fertile plants in the F2 and F3 from monosomic F1 indicated that chromosomes 1A and 7D of R1‐Lee, R2‐Sonora 64, R3, R4, and R5 had Rf‐genes. R2‐Sonora 64 and R5 each had a third Rf‐gene on chromosomes 6B and 7B, respectively. Primepi had Rf‐genes on chromosomes 1B and 5D. The inheritance of fertility restoration in control crosses and in some of the noncritical crosses indicated that R1‐Lee, R2‐Sonora 64, and R5 each had three Rf‐genes, and R3, R4, and Primepi each had two. The deficiency of certain chromosomes influenced the penetrance and expressivity of the Rf‐genes in certain crosses.

The inheritance of fertility restoration in male-sterile wheat carrying cytoplasm derived from Triticum timopheevi

The inheritance of the restoration of fertility in material carrying the cytoplasm of Triticum timopheevi was studied in F2, F3 and F4 generations. In the material used the segregation of restoration was shown to fit the hypothesis of three major, dominant, partially dominant or additive genes each of which made a different contribution to restoration but which acted cumulatively to produce the phenotypic expression observed.From the material it was possible to extract homozygous lines carrying known combinations of these three genes which can be used as tester lines to investigate the inheritance of genes for restoration derived from other sources.