Broadening the Genetic Basis for Crop Improvement: Interspecific Hybridization Within and Between Ploidy Levels in Helianthus

2017 ◽  
pp. 208-233
Keyword(s):  
Interspecific Hybridization ◽  
Genetic Basis ◽  
Crop Improvement ◽  
Ploidy Levels

scholarly journals Interspecific hybridization of sturgeon species affects differently their gonadal development

2017 ◽  
Vol 63 (No. 1) ◽  
pp. 1-10 ◽  
Author(s):  
Z. Linhartová ◽  
M. Havelka ◽  
M. Pšenička ◽  
M. Flajšhans
Keyword(s):  
Interspecific Hybridization ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Interspecific Hybrids ◽  
Gonad Development ◽  
Gonadal Development ◽  
Genetic Origin ◽  
Ploidy Levels ◽  
Sturgeon Species ◽  
Fertile Hybrids

Gonad development in fish is generally assumed to be negatively influenced by interspecific hybridization, resulting in sterility or sub-sterility. However, this is not the case in sturgeons (Acipenseridae), in which fertile hybrids are common. In the present study, we investigated gonad development in several sturgeon interspecific hybrids and purebred species. Six interspecific hybrid groups and three purebred groups were analyzed including 20 hybrid specimens with even ploidy, 40 specimens having odd ploidy levels, and 30 purebred specimens. Hybrids of species with the same ploidy (even ploidy – 2n, 4n) exhibited normally developed gonads similar to those seen in purebred specimens. In contrast, hybrids of species differing in ploidy (odd ploidy – 3n) did not display fully developed gonads. Ovaries were composed of oocytes or nests of differentiating oocytes that ceased development in early stages of meiosis (pachytene to zygotene) with a higher content of adipose and apoptotic tissue. Testes contained single spermatogonia along with Sertoli cells and spaces lacking germ cells. The obtained results showed that gonad development was influenced by genetic origin and ploidy of the sturgeon hybrids and were consistent with full fertility of hybrids with even ploidy. Sterility of females, but possibly limited fertility of males, is suggested for hybrids with odd ploidy.

scholarly journals Interspecific hybridization between diploid Fagopyrum esculentum and tetraploid F. homotropicum

2005 ◽  
Vol 85 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Yingjie Wang ◽  
Rachael Scarth ◽  
Clayton Campbell
Keyword(s):  
Interspecific Hybridization ◽  
Chromosome Numbers ◽  
Dna Analysis ◽  
Genetic Recombination ◽  
Diploid Species ◽  
Normal Growth ◽  
Colchicine Treatment ◽  
Chromosome Elimination ◽  
Ploidy Levels

The wild diploid species Fagopyrum homotropicum (2n = 2x = 16) has been used for buckwheat improvement, but, prior to this study, the tetraploid form (2n = 4x = 32) had not been hybridized with the cultivated species F. esculentum. The objective of this study was to hybridize F. esculentum with tetraploid F. homotropicum to increase the genetic variability. Forty-one interspecific F1 hybrids were obtained through ovule rescue in vitro, with hybridity confirmed using morphological characters, chromosome numbers (2n = 3x = 24) and DNA analysis. The F1 plants were mainly sterile. However, seven seeds were set spontaneously on two hybrid plants, and a large number of seeds were obtained after colchicine treatment. The F2 plants were divided into two groups based on chromosome numbers and morphology. The first group was hexaploid plants (2n = 6x = 48) or hypohexaploid plants (2n = 44–46), partially fertile with “gigas” features including increased height, dark green leaves, and large seeds with thick seed hulls. The second group of plants was diploid (2n = 2x = 16) (one plant had 17 chromosomes), with normal growth and fertility, and a combination of characters from both parents, indicating that genetic recombination had occurred during chromosome elimination. The diploid group was superior to the hexaploid group for use in buckwheat breeding programs due to the desirable characters and the ease of crossing. This is the first report of interspecific hybridization using different ploidy levels in the Fagopyrum genus. Key words: Buckwheat (F. esculentum; F. homotropicum), interspecific hybridization, breeding, tetraploid, diploid, hexaploid, fertility

Reciprocal differences of morphological and DNA characters in interspecific hybridization in Cucumis

2004 ◽  
Vol 82 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Jin Feng Chen ◽  
Fei Yun Zhuang ◽  
Xian An Liu ◽  
Chun Tao Qian
Keyword(s):  
Interspecific Hybridization ◽  
Random Amplified Polymorphic Dna ◽  
Female Parent ◽  
Stem Length ◽  
Maternal Transmission ◽  
Plant Materials ◽  
Banding Patterns ◽  
Ploidy Levels ◽  
Significant Difference ◽  
Reciprocal Differences

Plant materials with different ploidy levels from a series of reciprocal crosses between a wild Cucumis species (Cucumis hystrix Chakr., 2n = 2x = 24) and cucumber (Cucumis sativus L., 2n = 2x = 14) were used to investigate reciprocal differences in morphology, fertility, and DNA characteristics. Diameter of the stem, length of the petiole, and shape and size of the leaves of the hybrids were intermediate when compared with their parents. The length of the internode of the main stem showed maternal transmission in all hybrids, but the branching number and appearance of the first female flower showed paternal transmission. The differences in fertility of reciprocal plants were significant. When C. hystrix was used as the female parent, the diploid (2n = 2x = 19) hybrids set fruit without seeds, whereas the amphidiploid (2n = 4x = 38) plants produced fruits with viable seeds. However, when cucumber was used as the female parent, both tetraploid and diploid hybrid plants were highly sterile and did not set fruits. To further investigate variation in hybrid genomes, 21 arbitrary primers were used for random amplified polymorphic DNA analysis. Reciprocal differences were detected for 15 primers. The banding patterns were different among the four types of hybrids, but there was no significant difference in the total and (or) average numbers of bands observed. We suggest that the differences in random amplified polymorphic DNA banding patterns of the hybrids are probably related to the paternal- and (or) maternal-transmitted morphological characteristics in the reciprocal cross.Key words: Cucumis, interspecific hybridization, reciprocal differences, random amplified polymorphic DNA markers, paternal and (or) maternal transmission.

scholarly journals Comparative Studies of Intra and Inter Specific Hybrid of F2 Generations in Mungbean

2020 ◽  
pp. 01-11
Author(s):  
Pandiyan M ◽  
Krishnaveni A ◽  
Sivakumar P ◽  
Vaithiyalingan M ◽  
Jamuna E ◽  
...  
Keyword(s):  
Interspecific Hybridization ◽  
Wild Species ◽  
Interspecific Hybrids ◽  
Crop Improvement ◽  
Interspecific Crosses ◽  
Single Plant ◽  
Plant Yield ◽  
Biotic Stresses ◽  
Vigna Species ◽  
Specific Hybrid

Intra and interspecific hybridization was done for developing donor with respect to MYMV and Bruchids resistance. Several differences in many characters were observed in intra and interspecific hybrids crosses for certain characters. Among all the combination of both intra and interspecific crosses studied, single plant yield increased through only intra specific crosses attempted while resistance to biotic stresses like MYMV and bruchids were improved by interspecific crosses. Hence the utilization of wild species in crop improvement is very effective for donor development compared to intra specific crosses. Keywords: Vigna radiata; Wild Vigna species Intra and Interspecific; Hybridization; Comparative Traits

scholarly journals Genetic-basis analysis of heterotic loci in Dongxiang common wild rice (Oryza rufipogon Griff.)

2012 ◽  
Vol 94 (2) ◽  
pp. 57-61 ◽  
Author(s):  
XIAO-JIN LUO ◽  
XIAO-YUN XIN ◽  
JIN-SHUI YANG
Keyword(s):  
Wild Rice ◽  
Genetic Basis ◽  
Single Point ◽  
Crop Improvement ◽  
Dominant Gene ◽  
Introgression Line ◽  
Oryza Rufipogon ◽  
Cultivated Rice ◽  
Common Wild Rice ◽  
Point Analysis

SummaryHeterosis is widely used in genetic crop improvement; however, the genetic basis of heterosis is incompletely understood. The use of whole-genome segregating populations poses a problem for establishing the genetic basis of heterosis, in that interactions often mask the effects of individual loci. However, introgression line (IL) populations permit the partitioning of heterosis into defined genomic regions, eliminating a major part of the genome-wide epistasis. In our previous study, based on mid-parental heterosis (HMP) value with single-point analysis, 42 heterotic loci (HLs) associated with six yield-related traits were detected in wild and cultivated rice using a set of 265 ILs of Dongxiang common wild rice (Oryza rufipogon Griff.). In this study, the genetic effects of HLs were determined as the combined effects of both additive and dominant gene actions, estimated from the performance values of testcross F1s and the dominance effects estimated from the HMP values of testcross F1s. We characterized the gene action type at each HL. Thirty-eight of the 42 HLs were over-dominant, and in the absence of epistasis, four HLs were dominant. Therefore, we favour that over-dominance is a major genetic basis of ‘wild-cultivar’ crosses at the single functional Mendelian locus level.

scholarly journals Production of hybrid potatoes: Are heterozygosity and ploidy levels important?

2019 ◽  
pp. 687-694
Author(s):  
Jane Muthoni ◽  
Hussein Shimelis ◽  
Rob Melis
Keyword(s):  
Genetic Basis ◽  
Potato Breeding ◽  
Allelic Diversity ◽  
Solanum Species ◽  
Ploidy Levels ◽  
Cultivated Potato ◽  
Tetraploid Level ◽  
Diploid Level ◽  
Do So

It has been proposed that maximizing heterosis for yield in potato may be achieved by maximizing heterozygosity and associated intra and interlocus interactions. Tetraploids offer more opportunities to create such interactions than diploids hence the general observations that tetraploids are higher yielding than diploids. Consequently, efforts have been made to increase heterozygosity in tetraploids by introgressing allelic diversity from other Solanum species into cultivated potato. However, conventional potato breeding is difficult because the cultivated potato is an autotetraploid with tetrasomic inheritance and it comprises highly heterozygous individuals which suffer inbreeding depression upon selfing; breeding at the tetraploid level is slow and less efficient than at diploid level. At the diploid level, it is possible to breed for and fix traits under recessive genetic control; it is nearly impossible to do so at the tetraploid level. There is also rapid response to selection due to greater variation in diploids than tetraploids. Consequently, there have been efforts to convert potato from an asexually propagated tetraploid crop into an inbred seed-propagated diploid; this is by production of inbred lines through selfing of the tetraploids to assemble desirable combinations of genes in the inbreds. These efforts are at the experimental stages and a lot of research needs to be done before they are confirmed. Because currently there is little experimental evidence to support superiority of the inbred seed-propagated diploid strategy, it appears the theory that heterosis for yield in potato may be achieved by maximizing heterozygosity and associated intra and interlocus interactions remain unchallenged; these interactions are more in tetraplods than in diploids. This paper therefore looks at genetic basis of yield heterosis in cultivated potato and the role of heterozygosity and ploidy level in production of hybrid potatoes.

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