scholarly journals Genetical and Cytological Studies in Hybrid Roses

1924 ◽  
Vol 1 (4) ◽  
pp. 557-570
Author(s):  
KATHLEEN B. BLACKBURN ◽  
J. W. HESLOP HARRISON
Keyword(s):  
Chromosome Number ◽  
Pollen Parent ◽  
Egg Cell ◽  
Generative Nucleus ◽  
Seed Parent ◽  
Reciprocal Crosses ◽  
The Cross

1. Rosa Sabini and R. Wilsoni are reciprocal crosses between R. pimpinellifolia and some Tomentosa microgene. 2. Rosa pimpinellifolia is a balanced tetraploid, both the egg cell and the generative nucleus possessing 14 chromosomes. 3. The Tomentosa microgenes are unbalanced pentaploids, the microspores, when functional, carrying 7 chromosomes in their nuclei, and the egg cells 28. 4. Reciprocal crosses between R. pimpinellifolia and tomentosa forms should not therefore agree in chromosome complements. With pimpinellifolia as seed parent the cross should have 14 + 7 ( = 21) in its somatic nuclei, and with the same plant as pollen parent the number should be 28 + 14 ( = 42). 5. R. Wilsoni undoubtedly has R. pimpinellifolia as seed parent, yet its chromosome number is 42. 6. It has, therefore, like Primula Kewensis, doubled its original complement. 7. In doing so, again like that hybrid, it has attained fertility.

COMPARISON OF CULTIVAR HYBRIDS AND BLENDS WITH PURE CULTIVARS IN CRESTED WHEATGRASS

1979 ◽  
Vol 59 (4) ◽  
pp. 1019-1023 ◽  
Author(s):  
R. P. KNOWLES
Keyword(s):  
Agropyron Cristatum ◽  
Pollen Parent ◽  
Seed Parent ◽  
Average Yield ◽  
Crested Wheatgrass ◽  
The Cross

Four strains of crested wheatgrass were allowed to interpollinate in pairs to form hybrids which were subsequently compared with parents and seed blends of parents for hay production. Average yield gains of 2–3% were obtained for hybrids relative to parental averages while that of blends was 0–1%. Certain combinations gave somewhat greater gains such as 4–8% for the cross Summit × Nordan relative to the higher yielding Summit parent. The degree of hybridization varied from 0 to 56% with an average of 16% in the first set of crosses and 21% in the second set. The. colchicine-induced tetraploid of Agropyron cristatum (L.) Gaertn. as seed parent showed little crossing with the natural tetraploid A. desertorum (Fisch.) Schult., but 12–34% when used as the pollen parent.

Red Clover Seed‐Parent and Pollen‐Parent Correlated Reproductive Success and its Relationship to Polycross Mating Metrics

Crop Science ◽  
2018 ◽  
Vol 58 (2) ◽  
pp. 608-616
Author(s):  
Heathcliffe Riday ◽  
John A. Raasch ◽  
Sofie G. Dial
Keyword(s):  
Reproductive Success ◽  
Red Clover ◽  
Pollen Parent ◽  
Seed Parent ◽  
Clover Seed

Genetics: the centre of science

1966 ◽  
Vol 164 (995) ◽  
pp. 154-166 ◽  
Keyword(s):  
General Principle ◽  
Pollen Parent ◽  
Seed Parent ◽  
Crossing Experiments ◽  
Basic Principles ◽  
Isaac Newton ◽  
Large Numbers ◽  
The Difference

It is not often possible to pinpoint the origin of a whole new branch of science accurately in time and place, because, as Isaac Newton said, there are usually so many precursors on whose shoulders the successor stands and is thereby able to see further than they. But genetics is an exception, for it owes its origin to one man, Gregor Johann Mendel, who expounded its basic principles at Brno on 8 February and 8 March 1865. If a precursor is a man who, at an earlier date, makes a discovery which his successor is able to expand into a general principle of universal validity, Mendel had no precursors. There were not wanting breeders who hybridized plants: Joseph Gottlieb Koelreuter, Carl Friedrich von Gaertner, and William Herbert, to mention only the chief names, but what they were studying was not really basic genetics at all. They wanted to know if sterility in a hybrid is the fault of the pollen-parent or the seed-parent, whether either parent could be held responsible for the characters of different specified regions of the plant, or which had prepotency over the characters of the hybrid. The parent races that they chose for their crossing experiments were either different species, or varieties differing in large numbers of characters, and the results which they obtained were chaotic, inconstant, and contradictory, and led to no general principles at all. This was the difference between previous attempts to study heredity, and the Mendelian revolution that resulted in genetics.

The cytogenetics of the differences between some Secale species

1955 ◽  
Vol 46 (3) ◽  
pp. 377-383 ◽  
Author(s):  
Ralph Riley
Keyword(s):  
Secale Cereale ◽  
Chromosome Structure ◽  
Plant Morphology ◽  
Structural Condition ◽  
Evolutionary Significance ◽  
Seed Parent ◽  
Ear Morphology ◽  
The Cross ◽  
Fourth Pair

1. The seed of crosses of Secale cereale with S. montanum and S. dalmaticum germinated only when S. cereale was the seed parent.2. S. cereale was found to differ from S. montanum and S. dalmaticum by two large translocations involving three pairs of chromosomes, and a small translocation involving a fourth pair. The fertility of the F1 plants was low, and in ear morphology and perennial habit they were similar to the S. montanum and S. dalmaticum parents.3. S. montanum and S. dalmaticum were found to be similar in gross chromosome structure and their hybrids were phenotypically intermediate and fertile.4. The F2 of the cross S. cereale x S. dalmaticum consisted of three types, in terms of chromosome structural condition and plant morphology, those like one or other parent and those like the F1.5. The genetic and evolutionary significance of this situation is discussed, together with the problem of the fixation of translocations in populations.

Apospory in Paspalum thunbergii

2004 ◽  
Vol 52 (1) ◽  
pp. 81 ◽  
Author(s):  
Guohua Ma ◽  
Xuelin Huang ◽  
Nanxian Zhao ◽  
Qiusheng Xu
Keyword(s):  
Chromosome Number ◽  
Developmental Stage ◽  
Pollen Viability ◽  
Paraffin Section ◽  
Embryo Sac ◽  
Low Frequency ◽  
The Other ◽  
Egg Cell ◽  
Successive Generations ◽  
Mother Cells

The cytology, development of aposporous embryo sac, pro-embryo and pseudogamy in Paspalum thunbergii Kunth ex Steud. was studied. P. thunbergii was found to be a tetraploid cytotype, with a chromosome number of 40. Meiosis of the pollen mother cells was irregular, pollen viability was low and multiporate pollens were often observed. Megasporogenesis began normally; however, the megaspore deteriorated at the developmental stage of tetrad, while one to five specific nucellar cells became active and began enlarging, and then developed into aposporous embryo sacs. The mature aposporous sacs usually had three nuclei characterised by one egg cell and two polar nuclei. The egg cell developed spontaneously to form pro-embryos prior to anthesis. When several aposporous sacs occurred in the same ovule, usually one sac near the micropyle was involved in pseudogamy, while the other sacs were not involved. Low frequency of twin-embryo seedlings was observed after seeds matured. Examination of three successive generations by paraffin-section and clearing methods revealed that no sexual sac was present. Therefore, the species P. thunbergii is considered to be an obligate apomict that reproduces by apospory.

scholarly journals Auto-sexing potential and growth performance in Rhode Island, Nigerian local chickens and their reciprocal crosses

2020 ◽  
Vol 46 (5) ◽  
Author(s):  
A. E. Jubril ◽  
T. R. Fayeye ◽  
A. A. Ademola ◽  
H. H. Gunn
Keyword(s):  
Body Weight ◽  
Rhode Island ◽  
Plumage Colour ◽  
Chi Square ◽  
Reciprocal Crosses ◽  
Colour Inheritance ◽  
Significant Difference ◽  
The Cross ◽  
Chi Square Analysis ◽  
Local Chickens

This study was conducted to determine auto-sexing potential in Rhode Island, Nigerian local chicken and their reciprocal crosses. A total of 241 eggs were set in the incubator to determine the fertility, hatchability, % Hatch, % dead in shell, % dead in cell and % deformed chicks in the four genotypes (Rhode Island Red (RIR) x Rhode Island White (RIW), Rhode Island Red (RIR) x Rhode Island White (RIW), Nigerian Local Red (NLR) x Rhode Island White (RIW) and Nigerian Local Red (NLR) x Nigerian Local White (NLW). Only 94 eggs were hatched. RIRXRIW crossbred chicks had the highest percentage fertility of 88.89% followed by RIRxRIW (86.27%), NLRXRIW (77.36%) and NLRxNLW (72.31%), respectively. RIRxNLW had the highest percentage hatchability of 65.19%, followed by RIRxRIW (51.56%), NLRxNLW (51.06%) and NLRxRIW (24.39%). It was observed in the hatch-out analysis that the cross between NLRxRIW had the highest percentage of dead in shell (29.27%) followed by RIRxRIW (17.19%), NLRxNLW (17.02%) and RIRxNLW (11.36%), respectively. The highest percentage of dead in cell was recorded in NLRxRIW crossbred (43.33%), followed by NLRxNLW (31.92%), RIRxRIW (28.13%) and RIRxNLW (15.91%). The observed deformed chicks were highest in NLRxNLW (20.85%) followed by RIRxNLW (10.34%), RIRxRIW (6.06%) and NLRxNLW (0%), respectively. Also observed was the occurrence of bangers with NLRxRIW, having the highest occurrence of bangers (9.08%) and with NLRxNLW having no occurrence of bangers. The records of weekly body weight were taken on the 94 chicks and chi square analysis was used to test colour inheritance of chicks. Significant (P<0.05) difference was observed among genotypes in body weight of chicks at hatch and from weeks 1 to 8 weeks of age. The observed changes on body weight from 0 to 8th week of age of chicks showed significant difference across the four different genetic crossed groups (P<0.05) and weight at the 8th week showed that the cross between RIRxRIW (216.93g) had better in growth as compared to the cross between NLRxRIW (202.75g) and NLRxNLW (193.17g) which were statistically similar (P>0.05) and RIRxNLW (179.75g) crossbred chicks which had the lowest bodyweight at 8 weeks of age. The chi square (X2) analysis revealed that both RIRxRIW and NLRxRIW crossbred chicks were autosexed. The study concluded that selection for plumage colour showed great potential in determining the probability of chicks being autosexed. Also, pure bred of RIRXRIW and reciprocal cross of NLRXRIW showed great potential of producing autosexed chicks, while results on the direct crosses of NLRXNLW and RIRXNLW suggest that the pattern of inheritance of plumage colour is not simple. The study recommends further investigation to further ascertain the mode of plumage colour inheritance in the Nigerian Local Chickens.

scholarly journals EVALUATION OF MENTOR POLLINATION FOR BLUEBERRY BREEDING

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1072b-1072
Author(s):  
Timothy F. Wenslaff ◽  
Paul M. Lyrene
Keyword(s):  
Pollen Parent ◽  
Seed Parent ◽  
Hybrid Seeds ◽  
Multiple Pollen ◽  
Number Of Seeds ◽  
Vaccinium Elliottii

Two clones of anthocyanin-deficient (AD) Vaccinium elliottii (2×, homozygous recessive, yy) were used as seed parents in experiments combining normal and AD pollen. AD gives a seedling marker to distinguish the pollen parent. In the first experiment, flowers were pollinated daily for one, two, three or four days. AD and normal V. elliottii pollen were applied on separate days. The last day of each treatment received the opposite genotype from the previous day(s). The first pollination gave as many, or more, seedlings as later applications but the number of seeds per fruit was higher with multiple pollen applications. The second experiment used pollen from normal V. corymbosum (4×) alone or mixed with AD pollen from the 2× clones. Results depended on the seed-parent genotype. There was no difference between treatments in the number of hybrids produced by W81-1, which tends to set fruit even with only one seed per berry. Only mixed pollen yielded hybrids from clone FL83-139, which was never observed to produce berries with only one seed; apparently the mentor AD pollen helps to set the fruit, thereby allowing the rare hybrid seeds to develop.

scholarly journals Fine structure of plastids during androgenesis in Hordeum vulgare L.

2014 ◽  
Vol 49 (3) ◽  
pp. 205-210 ◽  
Author(s):  
Fortunat Młodzianowski ◽  
Krystyna Idzikowska
Keyword(s):  
Fine Structure ◽  
Hordeum Vulgare ◽  
Cross Section ◽  
Egg Cell ◽  
Hordeum Vulgare L ◽  
Starch Grains ◽  
Ultrathin Sections ◽  
The Cross ◽  
Plastid Ribosomes ◽  
Fertilized Egg

The fine structure of plastids was studied in the course of androgenesis in in the pollen of <em>Hordeum vulgare</em> L. It was found that these organelles occur in all stages of androgenesis. Their structure was simple and was frequently manifested on the cross section only by the presence of the envelope and matrix of different degree of density. Single thylakoids, nucleoid-like regions and starch grains were, however, also noted. The structure of plastids in embryoids formed from microspores of barley was compared with embryos developed from fertilized egg cell, and we did not found any fundamental differences between them. However, only plastid ribosomes were difficult to identify on ultrathin sections in embryoids and in the embryos.

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