Relationship in annual species of Medicago. II. Interspecific crosses between M. tornato (L.) Mill. and M. littoralis Rhode.

1965 ◽  
Vol 16 (1) ◽  
pp. 51 ◽  
Author(s):  
JP Simon

Six hybrids were obtained from 212 reciprocal crosses between M. littoralis Rhode and M. tornata (L.) Mill. The hybrids were chlorophyll-deficient in the early seedling stage but later development was normal although growth was retarded. The morphological characteristics were intermediate between those of the parents. Pollen fertility and seed set amounted to 7 and 10% respectively. Meiotic irregularities indicate that M. littoralis is differentiated from M. tornata by at least one translocation. The contribution of the structural changes in the chromosomes accounted for about 60% of the observed pollen sterility.

1968 ◽  
Vol 10 (3) ◽  
pp. 536-544 ◽  
Author(s):  
K. Lesins

A good seed set was obtained from crosses of Medicago glomerata Balb. with M. sativa L. There was no evidence of a preferential chromosome pairing effect on segregation for floral anthocyanin. From an analysis of different M. glomerata × M. sativa crosses four factors were found to be involved in anthocyanin production. About 90% of the cells showed normal chromosome behavior during meiosis. Taxonomically, M. glomerata stands somewhat apart from the M. sativa — falcata complex, as indicated by a lower seed set from intercrossed F1's, and by somewhat higher numbers of meiotic irregularities in the F1 plants. With these and other morphological differences M. glomerata is considered as a separate species. When hybridized with M. prostrata Jacq., M. glomerata responded in a similar manner to that of M. sativa. The weight of seeds produced by M. glomerata plants was approximately the same, whether fertilized by M. glomerata or by M. sativa pollen. There is a somewhat greater affinity between M. glomerata and M. prostrata than between M. sativa and M. prostrate; M. prostrata plants fertilized by M. glomerata pollen had better seed development than those fertilized by M. sativa.


Author(s):  
Aradhana Phukan ◽  
P. K. Barua ◽  
D. Sarma ◽  
S. D. Deka

Two CMS lines, IR 58025A and IR 68888A along with their maintainers and two fertility restorers, LuitR and IR 36R, were evaluated for flower and plant characters during early ahu (February-June) and kharif (July-November) seasons. IR 58025A showed longer stigmata and styles, and higher spikelet Length/Breadth (L/B) ratio while IR 68888A showed broader stigmata and wider glume opening angle in both the seasons. IR 68888A also exhibited higher pollen sterility during early ahu. IR 36R was characterized with broad anthers. LuitR showed longer and broader anthers with more pollen than others. Plant height, flag leaf length, flag leaf width and area were higher in IR 36R. Panicle exsertion was complete in pollen parents whereas it was 78-80% in CMS lines. The widest flag leaf angle was found in IR 58025B during early Ahu and in IR 36R during kharif. Kharif season was more favourable for growth of the plants with higher seed set percentage while floral traits of the CMS lines were better expressed in early Ahu. Manipulation of the seeding sequence of the parental lines in early Ahu is warranted for better seed set provided the seed crop escapes heavy premonsoon showers during reproductive stage. IR 68888A/LuitR was a good combination for pollen dispersal and seed setting.


1986 ◽  
Vol 64 (2) ◽  
pp. 282-291 ◽  
Author(s):  
V. Kaul ◽  
J. L. Rouse ◽  
E. G. Williams

Early events in the embryo sac of Rhododendron kawakamii and R. retusum have been studied after compatible self-pollinations and eight interspecific crosses, using sectioned ovaries, pistil squashes, and seed-set data. Ovules of Rhododendron kawakamii and R. retusum are anatropous, unitegmic, and tenuinucellate, with a typical eight-nucleate, seven-celled embryo sac. Fertilization normally occurs 4–5 days after pollination. The zygote lays down a callose wall but remains undivided during the first 13–15 days after pollination. The primary endosperm nucleus divides soon after fertilization, and development is cellular ab initio. Crosses of R. kawakamii (♂) with R. santapaui and R. retusum and crosses of R. retusum (♂) with R. kawakamii, R. santapaui, R. ovatum, and R. tashiroi showed apparently normal fertilization in a majority of ovules entered by pollen tubes. In crosses of R. kawakamii (♂) with R. quadrasianum and Kalmia latifolia entry of pollen tubes into ovules was delayed and frequently abnormal. Apart from compatible self-pollinations of R. kawakamii an R. retusum, only the cross of R. kawakamii (♂) with R. santapaui produced healthy seedlings. Of the remaining seven interspecific crosses only three showed significant embryo development in control pistils left to mature in situ. Similarities and differences in the breeding behaviour of R. kawakamii and R. retusum are discussed with reference to their taxonomic grouping within subsection Pseudovireya.


2020 ◽  
Vol 80 (01) ◽  
Author(s):  
J. Jorben ◽  
S. P. Singh ◽  
C. Tara Satyavathi ◽  
S. Mukesh Sankar ◽  
Jayant S. Bhat ◽  
...  

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.


2021 ◽  
Vol 27 (1) ◽  
pp. 68-73
Author(s):  
E.N. Shchurova ◽  
◽  
G.N. Filimonova ◽  
S.O. Ryabykh ◽  
◽  
...  

Introduction Morphological, biochemical and histopathological characteristics of paraspinal muscles have been well described in patients with idiopathic scoliosis. However, there is a paucity of literature on morphological picture of paraspinal muscles in patients with severe idiopathic scoliosis. Objective To explore how the magnitude of thoracic spine deformity affects morphological characteristics of paraspinal muscles in patients with severe idiopathic scoliosis. Material and methods A total 21 patients with idiopathic scoliosis were reviewed. The patients were assigned to two groups depending on magnitude of preoperative thoracic spine deformity. A major group consisted of patients with scoliosis of ≥ 60º (n = 11) and control group included patients with a curve < 60º (n=10). Biopsy samples were taken from muscle fragments (multifidus muscle) at the apex of the curve (major arc) at the Th6-Th10 level on the convex side while approaching to the posterior spinal structures during surgical correction of kyphoscoliosis using light microscope. The specimens were examined histologically with light microscope. Results Patients with severe idiopathic scoliosis (≥ 60º) showed evident muscle fiber atrophy and dystrophy of different extent. There were nucleus free areas and homogenized muscle fragments observed with connective tissue layers being swollen and frayed with multiple fibroblasts seen in nearly all the samples. Arterial walls were normally fibrotized. Structural changes ranged from minimal with a curve of 60º to degrading muscles with the fibers replaced by fat and connective tissues with a curve angle of 145º. Conclusion Morphological characteristics of paraspinal muscles have been shown to be severely affected by the magnitude of thoracic spine deformity in patients with severe idiopathic scoliosis. The findings should be considered in surgical correction of kyphoscoliosis with special focus on postoperative vascular and neurotropic therapy to allow wound healing and lower complication rate.


Helia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Katerina Vedmedeva ◽  
Tatiana Machova

Abstract Sunflower is used for the production of oil, confectionery and animal feed. Birds are very fond of sunflowers and can be pests of sunflower crops, and are consumers of seeds. Sunflower poultry feed is an emerging market that determines the direction of breeding. Its development is based on the determination of bird preferences and the available variety of sunflower lines. This is what our research is devoted to. Experimental feeding of chickens with a mixture of sunflower seeds of different colours was carried out. Chickens have been found to prefer contrasting striped seeds with white and dark stripes more than others. The white colour of the seeds was eaten less than others. Studies of the genetics of sunflower colour allow us to distinguish two groups of lines by seed colour. The first has white seeds with the EwEwPP genotype, suitable for use in human confectionery and more protected from being eaten by wild birds in the fields. The second is striped seeds with the EstrEstrPP genotype, which can be fed whole seeds to birds. Donors of seed colour traits and other traits important for hybrid breeding were selected from the evaluated collection of sunflower lines. InK1039 line is a donor of small striped seeds and pollen fertility restoration. InK1587 line is a sterility fixer and donor of striped and early maturing seeds. To create hybrids with white seeds for human consumption and thus more resistant to ingestion by wild birds, white seed donors were isolated with KG9 to restore pollen fertility and I2K2218 in a pollen sterility fixer.


1987 ◽  
Vol 65 (6) ◽  
pp. 1212-1217 ◽  
Author(s):  
Christopher A. Tabor ◽  
Neal M. Barnett

An experimental culture system was devised that provided a reliable means for conducting quantitative studies on interrelationships between embryos and megagametophytes of Pinus strobus L. during germination and early seedling development. By controlling imbibition rates, it was possible to synchronize germination of intact megagametophytes and obtain cultures with uniform morphological characteristics for use in biochemical studies. Early seedling development was affected by time of removal of the megamametophytes from the embryos; organs were larger if magagametophytes were left intact for longer periods of time. By using a nitrate reductase semimicro assay, enzyme activity was detected in embryos and shoots of intact megagametophytes, but activity declined as the seedlings aged. Activity within roots increased as seedlings matured and may be localized in the root tip. Nitrate was produced within the megagametophyte; however enzyme activity was dependent upon sustained, direct access to the inducing substrate, nitrate, in the culture medium. When megagametophytes remained intact for the initial 8 days of germination, seedlings developed epicotyls, and nitrate reductase activity within the roots was significantly greater than in 6-day cultures; in essence, by 8 days these seedlings appeared to have passed a threshold and were autotrophic.


2014 ◽  
Vol 8 ◽  
pp. 120-126 ◽  
Author(s):  
Bal K. Joshi ◽  
Laxmi P. Subedi ◽  
Santa B. Gurung ◽  
Ram C. Sharma

Pollen analysis can be used to discriminate between different species, identify possible  interspecies hybrids, identify restorer and maintainer lines, useful to study genetics of  restorer gene, interaction between chromosome and cytoplasm and relationship between  parents. Pollen abortion system of male sterility is an important tool in hybrid rice  production and spikelet is the major yield components. Nine improved cultivars, six  landraces and three wild aborted cytoplasmic-genetic male sterile (CMS) lines were used to  analyze pollen and spikelet in F1 rice hybrids and their parents. The frequency of pollen  categories and its relationship to spikelet fertility were investigated. Pollen sterility of the  F1s was determined by staining pollen grains in 1% potassium iodide-iodine (I-KI) solution.  Spikelet fertility was determined by counting the total number of seed set in proportion to  the total number of spikelets. Correlation and regression coefficients for some traits were  computed. In hybrids, pollen fertility ranged from 0.5 to 82% and spikelet fertility from 0 to  87%. Pollen fertility varied from 28 to 97%, while spikelet fertility from 73 to 91% in pollen  parents. The highest and the lowest percentages of pollen fertility were found in Chaite-6  and Chiunde cultivars respectively. Spikelet fertility percentage varied widely among  hybrids and many hybrids had lower spikelet fertility percentage than their parents.  Therefore, it is of practical importance to understand the causes of high spikelet sterility in  hybrids for possible increase in spikelet fertility. Highly significant positive correlation was  found between stained round fertile (SRF) pollen and spikelet fertility. The positive value of  correlation and regression coefficient on SRF and spikelet fertility were found between F1  and mid parent, and F1 and male parent. High fertility of cross may be due to the presence of  a wide compatibility gene or restorer genes in the cultivar. Lower pollen and spikelet  fertility of the crosses was attributed to effect of the genetic background of the tester parent. Nepal Agric. Res. J. Vol. 8, 2007, pp. 120-126 DOI: http://dx.doi.org/10.3126/narj.v8i0.11605  


1969 ◽  
Vol 20 (2) ◽  
pp. 227 ◽  
Author(s):  
KS McWhirter

A type of male sterility found in two Desmodium plants of probably interspecific hybrid origin was cytoplasmically inherited. The cytoplasmic male-sterile character was incorporated in the tropical legume Desmodium sandwicense by backcrossing. In this genetic background pollen sterility was complete. The male-sterile character was not graft-transmissible, and it produced no detectable pleiotropic effects on growth and development. Desmodium intortum gave restoration of pollen fertility in Fl hybrids with male-sterile lines of D. sandwicense. Restored F1 hybrids produced apparently normal pollen, but tests of functional ability of the pollen disclosed that pollen fertility was less than that of Fl hybrids with normal cytoplasm. Incomplete restoration of fertility was not due to heterozygosity of fertility-restoring genes with gametophytic expression, since fertility-restoring genes were shown to act sporophytically. The results established the occurrence in the legume Desmodium of a system of determination of the male-sterile, fertility-restored phenotypes that is similar to the cytoplasmic male sterility systems described in many other angiosperm plants. A scheme utilizing the genetic stocks produced in this study for commercial production of the interspecific hybrid D. sandwicense x D. intortum as a cultivar is presented.


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