STERILITY IN POTATOES

1941 ◽  
Vol 19c (5) ◽  
pp. 145-155 ◽  
Author(s):  
T. J. Arnason

Microspore tetrads were rarely formed in three male-sterile potato varieties studied. Dyads and triads were much more common. The failure of the second meiotic divisions appeared to be the main reason for the lack of tetrads. Many of the microspores aborted without enlarging, some did grow, however, and round off. In presumably mature anthers from open flowers, microspores were very variable in size and in the appearance of the nucleus and cytoplasm. Anther pores usually failed to open. The pollen-fertile varieties formed microspores that were almost entirely in tetrads. Mature anthers had roomy locules, open anther pores, and large numbers of uniform, sound-appearing pollen grains. They contained also some empty grains. About one-half the grains from one pollen-fertile line were empty. Abscission of buds and flowers is an important factor contributing to sterility or at least unfruitfulness in many potato varieties, including the three male-sterile ones reported in this paper. Following pollination with sound pollen, a few seeds have been obtained, though with some difficulty, from each of the male-sterile lines. Premature flower abscission rather than female sterility appears to be the main bar to seed production when sound pollen is applied.

1943 ◽  
Vol 21c (2) ◽  
pp. 41-56 ◽  
Author(s):  
T. J. Arnason

Between 600 and 900 ovules are estimated to begin development in single normal potato ovaries. The number of seeds per fruit ranged from 0 to 183 in 1941, from 7 to 472 in 1942.Sectioned ovules from several potato varieties were examined. Estimates of the proportion of aborted ovules from freshly opened flowers or nearly mature buds were as follows: Minn. 75-5: 10%, Earlaine: 15%, Early Ohio: 20%, Irish Cobbler: 30–40%, Sebago: 60%, U.S.D.A. 46000: 80%, Netted Gem: 100%. Pollen from the first two varieties only in this list has been used successfully in crosses. In Netted Gem few gametophytes began development, most of the abortion occurring earlier. In the other varieties a larger proportion of the abortion became evident after gametophyte development had been initiated. In Sebago many embryo sacs were immature in freshly opened flowers. Inexact distribution of chromosomes at meiosis probably accounts for a part of the observed abortion. Sterility genes may be responsible for a part. Premature bud and flower abscission lowers the expressed fertility of all varieties but is more effective in some: e.g. Netted Gem and Early Ohio, than in others, e.g. Minn. 75-5 and Earlaine. Fertilization in Irish Cobbler occurred mainly two to four days after pollination; 50% of ovules in the upper half of the ovary showed endosperm divisions. Evidence of fertilization was seen in less than 5% of ovules of U.S.D.A. 46000 taken four days after pollination. Nutritive cells of the integument became considerably enlarged in many ovules containing aborted embryo sacs.


2016 ◽  
Vol 9 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Sharon Gillies ◽  
David R. Clements ◽  
Jennifer Grenz

AbstractMore than 100 years ago, Japanese knotweed was introduced to North America. Given its vigorous rhizome system and capability to grow from rhizome and stem fragments, it persists and spreads locally, forming monotypic stands. The Japanese knotweed clone originally introduced was a male sterile female clone; thus, early in the invasion, reproduction from seed was not an issue. The implication was that long-distance dispersal was relatively rare. However, recently, widespread hybridization between Japanese knotweed and Sakhalin (giant) knotweed has been reported, with the hybrid species, Bohemian knotweed, forming the majority of knotweed plants in many areas and possessing higher variability than the parent species. The hybrids produce large numbers of wind-dispersed viable seeds that germinate at rates approaching 100% in some populations. As temperatures increase, knotweed is predicted to expand its range farther north and to higher elevations. With the ability to regenerate from vegetative fragments and disperse via seeds, invasive knotweed species are on the move. An arsenal of chemical weapons, the ability to shade out competitors, and the ability to adapt rapidly through epigenetic change makes knotweed a formidable invader. We observed that knotweed species clearly possess 8 of the 12 ideal weed characteristics, with Bohemian knotweed likely exhibiting still more because of prolific seed production. More research is needed to answer pressing questions. How does hybridization affect knotweed epigenetics? Under what conditions might seed production become more frequent? What kind of niche expansion is possible with the increased variability? Given the considerable challenges posed by knotweed species that promise to become even greater with the proliferation and spread of Bohemian ecotypes, only a thoroughly researched, well-informed approach to knotweed management across North America can be successful.


Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
G. D. Prahalada ◽  
Balram Marathi ◽  
Ricky Vinarao ◽  
Sung-Ryul Kim ◽  
Reynaldo Diocton ◽  
...  

AbstractHigh seed cost due to poor seed yield severely limits the adoption of hybrid rice by farmers. Increasing the out-crossing rate is one of the key strategies to increase hybrid seed production. Out-crossing rate is highly influenced by the size of female floral traits, which capture pollen grains from male donor plants. In the current study, we identified 14 QTLs derived from the perennial wild rice Oryza longistaminata by composite interval mapping for five key floral traits: stigma length (five), style length (three), stigma breadth (two), stigma area (one), and pistil length (three). QTL analysis and correlation studies revealed that these stigma traits were positively correlated and pleiotropic to the stigma length trait. We selected the major-effect QTL qSTGL8.0 conferring long stigma phenotype for further fine mapping and marker-assisted selection. The qSTGL8.0 (~ 3.9 Mb) was fine mapped using newly developed internal markers and was narrowed down to ~ 2.9 Mb size (RM7356–RM256 markers). Further, the flanking markers were validated in a segregating population and in progenies from different genetic backgrounds. The markers PA08-03 and PA08-18 showed the highest co-segregation with the stigma traits. The qSTGL8.0 was introgressed into two cytoplasmic male sterile (CMS) lines, IR58025A and IR68897A, by foreground, background, and trait selection approaches. The qSTGL8.0 introgression lines in CMS backgrounds showed a significantly higher seed setting rate (2.5–3.0-fold) than the original CMS lines in test crosses with their corresponding maintainer lines. The newly identified QTLs especially qSTGL8.0, will be quite useful for increasing out-crossing rate and this will contribute to increase seed production and decrease seed cost.


2019 ◽  
Vol 40 (04) ◽  
Author(s):  
Pramod Sharma ◽  
Sunil A Nair ◽  
Payal Sharma

Male sterility is described as absence of functional pollen grains in hermaphrodite flowers facilitating large scale production of hybrid seeds in vegetable crops. It eases hybrid seed production at commercial level in crops like tomato, chilli, capsicum, carrot, onion, cabbage, cauliflower and cucurbits. Male sterility would reduce the cost of hybrid seed production by limiting the labour making it efficient and economical. Incorporation of biotechnological tools in conventional plant breeding techniques would aid the breeders in limiting the drawbacks surrounding exploitation of male sterility for development of new hybrids. The present review is an attempt to summarize and to know the commercial utilization of male sterile line in hybrid seed production of vegetables.


2021 ◽  
Author(s):  
G.D. Prahalada ◽  
Balaram Marathi ◽  
Ricky Vinarao ◽  
Sung-Ryul Kim ◽  
Reynaldo Diocton ◽  
...  

Abstract Background: High seed cost due to poor seed yield severely limits the adoption of hybrid rice by farmers. Increasing the out-crossing rate is one of the key strategies to increase hybrid seed production. Out-crossing rate is highly influenced by the size of female floral traits, which capture pollen grains from male donor plants. Results: In the current study, we identified 14 QTLs derived from the perennial wild rice Oryza longistaminata by composite interval mapping for five key floral traits: stigma length (five), style length (three), stigma breadth (two), stigma area (one), and pistil length (three). QTL analysis and correlation studies revealed that these stigma traits were positively correlated and pleiotropic to the stigma length trait. We selected the major-effect QTL qSTGL8.0 conferring long stigma phenotype for further fine mapping and marker-assisted selection (MAS). The qSTGL8.0 (~3.9 Mb) was fine mapped using newly developed internal markers and was narrowed down to ~2.9 Mb size (RM7356‒RM256 markers). Further, the flanking markers were validated in a segregating population and in progenies from different genetic backgrounds. The markers PA08-03 and PA08-18 showed the highest co-segregation with the stigma traits. The qSTGL8.0 was introgressed into two cytoplasmic male sterile (CMS) lines, IR58025A and IR68897A, by foreground, background, and trait selection approaches. Conclusion: The qSTGL8.0 introgression lines in CMS backgrounds showed a significantly higher seed setting rate (2.5‒3.0-fold) than the original CMS lines in testcrosses with their corresponding maintainer lines. The newly identified QTLs especially qSTGL8.0, will be quite useful for increasing out-crossing rate and this will contribute to increase seed production and decrease seed cost.


2012 ◽  
Vol 60 (6) ◽  
pp. 506 ◽  
Author(s):  
Priscila Andressa Cortez ◽  
Sandra Maria Carmello-Guerreiro ◽  
Simone Pádua Teixeira

Pollen abortion occurs in virtually all species and often does not prejudice reproductive success. However, large numbers of abnormal pollen grains are characteristic of some groups. Among them is Miconia, in which partial and complete male sterility is often related to apomixis. In this study, we compared the morphology of pollen grains over several developmental stages in Miconia species with different rates of male sterility. Our aim was to improve the knowledge of mechanisms that lead to male sterility in this ecologically important tropical group. Routine techniques for microscopy were used to examine anthers in several developmental stages collected from the apomictic species Miconia albicans and M. stenostachya. Both species are completely male sterile since even the pollen grains with apparently normal cytoplasm were not able to develop a pollen tube. Meiosis is a rare event in M. albicans anthers and happens in an irregular way in M. stenostachya, leading to the pollen abortion. M. albicans has more severe abnormalities than M. stenostachya since even the microspores and pollen grain walls were affected. Moreover, in M. stenostachya, most mitosis occurring during microgametogenesis was also abnormal, leading to the formation of bicellular pollen grains with two similar cells, in addition to the formation of pollen grains of different sizes. Notably, abnormalities in both species did not reach the production of Übisch bodies, suggesting little or no tapetum involvement in male sterility in these two species.


2021 ◽  
Vol 22 (13) ◽  
pp. 6877
Author(s):  
Yannan Shi ◽  
Yao Li ◽  
Yongchao Guo ◽  
Eli James Borrego ◽  
Zhengyi Wei ◽  
...  

Recently, crop breeders have widely adopted a new biotechnology-based process, termed Seed Production Technology (SPT), to produce hybrid varieties. The SPT does not produce nuclear male-sterile lines, and instead utilizes transgenic SPT maintainer lines to pollinate male-sterile plants for propagation of nuclear-recessive male-sterile lines. A late-stage pollen-specific promoter is an essential component of the pollen-inactivating cassette used by the SPT maintainers. While a number of plant pollen-specific promoters have been reported so far, their usefulness in SPT has remained limited. To increase the repertoire of pollen-specific promoters for the maize community, we conducted a comprehensive comparative analysis of transcriptome profiles of mature pollen and mature anthers against other tissue types. We found that maize pollen has much less expressed genes (>1 FPKM) than other tissue types, but the pollen grain has a large set of distinct genes, called pollen-specific genes, which are exclusively or much higher (100 folds) expressed in pollen than other tissue types. Utilizing transcript abundance and correlation coefficient analysis, 1215 mature pollen-specific (MPS) genes and 1009 mature anther-specific (MAS) genes were identified in B73 transcriptome. These two gene sets had similar GO term and KEGG pathway enrichment patterns, indicating that their members share similar functions in the maize reproductive process. Of the genes, 623 were shared between the two sets, called mature anther- and pollen-specific (MAPS) genes, which represent the late-stage pollen-specific genes of the maize genome. Functional annotation analysis of MAPS showed that 447 MAPS genes (71.7% of MAPS) belonged to genes encoding pollen allergen protein. Their 2-kb promoters were analyzed for cis-element enrichment and six well-known pollen-specific cis-elements (AGAAA, TCCACCA, TGTGGTT, [TA]AAAG, AAATGA, and TTTCT) were found highly enriched in the promoters of MAPS. Interestingly, JA-responsive cis-element GCC box (GCCGCC) and ABA-responsive cis-element-coupling element1 (ABRE-CE1, CCACC) were also found enriched in the MAPS promoters, indicating that JA and ABA signaling likely regulate pollen-specific MAPS expression. This study describes a robust and straightforward pipeline to discover pollen-specific promotes from publicly available data while providing maize breeders and the maize industry a number of late-stage (mature) pollen-specific promoters for use in SPT for hybrid breeding and seed production.


Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jianxin Wu ◽  
Shijun Qiu ◽  
Menglong Wang ◽  
Chunjue Xu ◽  
Xing Wang Deng ◽  
...  

Abstract Background The third-generation hybrid rice technology can be constructed by transforming a recessive nuclear male sterile (NMS) mutant with a transgenic cassette containing three functional modules: the wild type male fertility gene to restore the fertility of the mutant, the pollen killer gene that specifically kills the pollen grains carrying the transgene, and the red fluorescence protein (RFP) gene to mark the transgenic seed (maintainer). The transgenic plant produces 1:1 NMS seeds and maintainer seeds that can be distinguished by the RFP signal. However, the RFP signals in the partially filled or pathogen-infected maintainer seeds are often too weak to be detected by RFP-based seed sorting machine, resulting in intermingling of the maintainer seeds with NMS seeds. Results Here we constructed a weight-based seed sorting system for the third-generation hybrid rice technology by silencing the genes encoding ADP-glucose pyrophosphorylase (AGP) essential for endosperm starch biosynthesis via endosperm-specific expression of artificial microRNAs (amiRNAs). In this system, the NMS seeds have normal endosperm and are heavy, but the maintainer seeds have shrunken endosperms and are light-weighted. The maintainer seeds can be easily and accurately sorted out from the NMS seeds by weight-sorting machines, so pure and fully filled NMS seeds are available. Conclusions The weight-based seed sorting system shows obvious advantages over the RFP-based seed sorting system in accuracy, efficiency, and cost for propagation of pure male sterile seeds. These characteristics will significantly increase the value and transgenic safety of the third-generation hybrid rice technology.


Author(s):  
Georgeta Oroian ◽  
G. Morar ◽  
I. Haş ◽  
Voichiţa Haş

The use of cytoplasmatic male-sterility in maize seed production contributes to increase economical efficiency and to obtain great genetical seeds. Through this theme one has followed the realization of a comparative study between some hybrids obtained to Turda on C and T cytoplasm their homologues, developed with normal and through the castration of the maternal parents. The researches aimed mainly the phenotypic and genotypic variability of the hybrids, the degree of male-sterility and the capacity of production, in phytotechnic conditions in different densities.


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