Euphytica

Zeven, A. C.

doi: 10.1007/bf00034093pmid: N/A

Male sterile “lines” are being made carrying either Ne1sor Ne2sin homozygous condition. The “lines” will be used to determine the necrosis genotype of wheat varieties and at the same time to trace genes restoring fertility in cytoplasmic sterile “lines”.It is suggested that hybrid necrosis could be used in hybrid seed production.The article is concluded with a list of 100 varieties and selections of which the genotype for hybrid necrosis is given.

Cleij, G.

doi: 10.1007/bf00034094pmid: N/A

Attempts have been made to find a method to control the male sterility-male fertility balance in beets. It proved not possible to induce male sterility in O-types by means of grafting. Nor was transmission by infection with aphids or by rubbing with juice successful.In some cases exposure of germinated seed of plasmatic male sterile annual beet material to temperatures of up to 55°C resulted in the occurrence of male fertile plants. The accompanying change could not be uniformly explained from the propagation obtained. It is possible that S-plasm has changed into N-plasm. Further investigations are in progress.

Ahloowalia, B. S.

doi: 10.1007/bf00034098pmid: N/A

Studies on induction, isolation and stabilization of tetraploids in Lolium perenne L. (2n=14) are reported. These investigations revealed that:The different varieties of ryegrass responded differentially to colchicine treatment.Colchicine was mutagenic in addition to doubling chromosome number in ryegrass.A high incidence of mixoploidy was obtained following colchicine treatment, which interfered with the fertility of the C0 tetraploids. The tillers, selected cytologically for tetraploid purity, had a higher seed set and 100-grain weight than either the mother plant or the diploid variety.In the C1 generation, obtained from the interpollination of pure tetraploid tillers, about 92 per cent plants were tetraploid (2n=28), 7 per cent aneuploid (2n=25, 26,27) and less than one per cent diploid.There was no significant difference in the percentage recovery of the tetraploids from small and large seeds in the C1 generation.

Mia, M. M.; Shaikh, A. Q.

doi: 10.1007/bf00034099pmid: N/A

Although numerous attempts have been made during the last five decades, no hybrids combining the qualities of the two commercially most important species have been released so far. Dry seeds of Corchorus capsularis L. var. D-154 and Corchorus olitorius L. var. C.G. were irradiated with gamma rays of various intensities from 70 Kr. to 100 Kr. and were sown in the field. Abnormal plants of the first generation showing bilobed and crinkled characters in their leaves induced by gamma rays were chosen as male parents. 300 crosses of different combinations were made. In all 120 fruits developed into maturity. All the seeds failed to germinate except those from the crosses ♀ C.G. (0 Kr.) × ♂ D-154 (80 Kr.) and ♀ D-154 (0 Kr.) × ♂ C.G. (70 Kr.). F1 plants from the cross ♀ C.G. (0 Kr.) × ♂ D-154 (80 Kr.) inherited the bilobed character of the male parent whereas the plants from the other cross failed to show any sign of inheritance of the male parent. This indicated that the plants from the cross ♀ C.G. (0 Kr.) × ♂ D-154 (80 Kr.) were hybrids. These hybrids attained a greater height than the controls and were highly fertile.

Quagliotti, L.

doi: 10.1007/bf00034102pmid: N/A

The effect of temperature on flower stalk development, flowering habit and sex expression in the carrot cultivar Amsterdam Forcing has been studied at 26°, 20° and 14°C.At the higher temperatures the growth rate of the vegetative frame of the plants was higher, but the ultimate size which they reached was smaller. Flowering was earlier at the higher temperatures.The number of umbels produced was greater at the higher temperatures, but their quality, as expressed in number of umbellets per umbel and number of flowers per umbellet, was better at the lower temperatures.At 14°C the ratio of hermaphroditic to male flowers was a little more in favour of the hermaphroditic flowers than at the higher temperatures; in the 3rd (or) 4th order umbels it was less so than in the earlier or later order umbels; in the 1 st position umbels it was more so than in the umbels of all later positions.While fertility of the male flowers was distinctly lowered by high temperatures, that of the hermaphroditic flowers was not significantly affected.

Natarajan, B. V.; Krishnamurthy, T. N.; Thuljaram Rao, J.

doi: 10.1007/bf00034103pmid: N/A

Studies on the relative effects of parents on some economic characters in sugarcane have given indications of maternal influence in the progeny performance in certain crosses with regard to millable canes at harvest, height of stalks and brix per cent in juice, irrespective of the fact that pollen parent effect was positive or negative.As judged from a study of the progeny of the direct crosses and reciprocals among the varieties studied, particularly use of Co. 678 as a pistil parent in the breeding programme for improving the mean height of the progeny and Co. 527 as a pistil parent for increasing number of millable canes at harvest and brix per cent in juice is clearly indicated. These indications should also prove useful for application in adopting the polycross method of breeding as well.