Seed set and seedling variation in greater yam (Dioscorea alata L.)

Abraham, K.; Nair, S. G.; Sreekumari, M. T.; Unnikrishnan, M.

doi:10.1007/bf00021841

Cited by 16 publications

(11 citation statements)

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“…Varietal diversity can be increased by controlled pollinations and breeding new cultivars and this has proven to be an effective way of genetic improvement [21, 22, 23, 68]. Most of the accessions included in our study are not fertile.…”

Section: Discussionmentioning

confidence: 99%

“…Most of the accessions included in our study are not fertile. Triploids are sterile [68, 69], as are several diploids and tetraploids. The results presented here allowed the identification of different groups of fertile cultivars with a good tolerance to anthracnose disease (Groups II, III, VI, XI, XVI and XVII) as well as several groups that contain cultivars known for the quality of their tubers: organoleptic, shape, dry matter content, and others (Groups III, VI, VII, VIII).…”

Section: Discussionmentioning

confidence: 99%

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Understanding the genetic diversity and population structure of yam (Dioscorea alata L.) using microsatellite markers

Arnau

Bhattacharjee

et al. 2017

PLoS ONE

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Yams (Dioscorea sp.) are staple food crops for millions of people in tropical and subtropical regions. Dioscorea alata, also known as greater yam, is one of the major cultivated species and most widely distributed throughout the tropics. Despite its economic and cultural importance, very little is known about its origin, diversity and genetics. As a consequence, breeding efforts for resistance to its main disease, anthracnose, have been fairly limited. The objective of this study was to contribute to the understanding of D. alata genetic diversity by genotyping 384 accessions from different geographical regions (South Pacific, Asia, Africa and the Caribbean), using 24 microsatellite markers. Diversity structuration was assessed via Principal Coordinate Analysis, UPGMA analysis and the Bayesian approach implemented in STRUCTURE. Our results revealed the existence of a wide genetic diversity and a significant structuring associated with geographic origin, ploidy levels and morpho-agronomic characteristics. Seventeen major groups of genetically close cultivars have been identified, including eleven groups of diploid cultivars, four groups of triploids and two groups of tetraploids. STRUCTURE revealed the existence of six populations in the diploid genetic pool and a few admixed cultivars. These results will be very useful for rationalizing D. alata genetic resources in breeding programs across different regions and for improving germplasm conservation methods.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Understanding the genetic diversity and population structure of yam (Dioscorea alata L.) using microsatellite markers

Arnau

Bhattacharjee

et al. 2017

PLoS ONE

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“…But the distribution of the levels of ploidy in the two sexes in relation to fertility had been ignored in those studies, presumably due to the constraints of non-flowering or erratic flowering and non-synchrony of the male and female phases (Sharma & De, 1956;Waitt, 1963;Martin, 1972;Onwueme, 1978;Abraham et al, 1986). However, Ramachandran (1968) had recorded the occurrence of hexaploids and octoploids (2n=60 and 80 respectively) in a few females and tetraploidy (2n=40) in the males.…”

Section: Discussionmentioning

confidence: 99%

“…Although genetic improvement by sexual hybridisation has considerably advanced in D. rotundata (Sadik, 1976;Abraham et al, 1989) the Asian yams are lagging behind in this respect. In D. alata (greater yam) sexual reproduction has been reported only recently in a few clones (Abraham et al, 1986;Bai & Jos, 1986). This has created interest in further searching for fertile types among cultivars.…”

Section: Introduction Materials and Methodsmentioning

confidence: 99%

Polyploidy and sterility in relation to sex in Dioscorea alata L. (Dioscoreaceae)

Abraham

Nair

1991

Genetica

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Chromosome numbers and fertility studies of 73 male and 30 female flowering germplasm accessions of Dioscorea alata L. were carried out. All males were tetraploids showing the same chromosome number (n = 20 or 2n :-40) and were pollen fertile (10.9-96.2%), most of them being highly fertile. Among the female the majority were higher ploids (hexa-and octoploids; 2n = 60 and 80) and sexually completely sterile. There were only two tetraploid female accessions which were sexually fertile. Pollination studies revealed that seed sterility in D. alata was due to female sterility associated with the occurrence of higher levels of ploidy. The female sex-limited occurrence of higher polyploidy and sterility observed in D. alata is a curious situation among dioecious higher plants.

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“…CROPPING SYSTEMS: TRENDS AND ADVANCES (Sadik and Okereke, 1975;Doku, 1985;Abraham et al, 1986) without tapping the benefit of characteristics from complex polyploid species. Improvements in screening methodologies are required to increase the efficiency and effectiveness of selection for resistance against pests and pathogens such as nematodes (Scutellonema sp., Pratylenchus sp., and Meloidogyne sp.…”

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confidence: 99%

Problems and Perspectives of Yam-Based Cropping Systems in Africa

Ekanayake

Asiedu

2003

Journal of Crop Production

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Yams (Dioscorea spp.) constitute an important starchy staple in sub-Saharan Africa (SSA) where food security for a growing population is a critical issue. Mixed cropping in yam based systems is the norm in the region and productivity of yams in these systems is below potential. It is concluded that there is much scope for improvement of yam based cropping systems in SSA in order to meet the needs of the region. The strategy of crop breeding to select yam varieties suitable for various cropping systems must consider a truly multidisciplinary systems approach. Further manipulation must be made to tuber dormancy to expand flexibility in field propagation in different cropping systems and improve storage and marketing. The sustainability of yam-based cropping systems in SSA could improve if agronomic research was focused Indira J. Ekanayake on strategies for improving soil fertility, weed and pest management including design of cropping systems and suitable rotations.

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Seed set and seedling variation in greater yam (Dioscorea alata L.)

Cited by 16 publications

References 1 publication

Understanding the genetic diversity and population structure of yam (Dioscorea alata L.) using microsatellite markers

Understanding the genetic diversity and population structure of yam (Dioscorea alata L.) using microsatellite markers

Polyploidy and sterility in relation to sex in Dioscorea alata L. (Dioscoreaceae)

Problems and Perspectives of Yam-Based Cropping Systems in Africa

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