All issues
Volume 24, Issue 5
Displaying 1-6 of 6 articles from this issue
- |<
- <
- 1
- >
- >|
-
Hikaru KUWADA1974 Volume 24 Issue 5 Pages 207-210
Published: October 31, 1974
Released on J-STAGE: May 16, 2008
JOURNAL FREE ACCESS(1) The reciprocal crosses between A. tuberculatus (2n=58) and A. Manihot (2n= 68) were made in order to make clear their genome relationship and to breed the hybrids. (2) The interspecific hybridizatidn was successful only when A.tuberculatus was used as female. (3) The size of F1 seeds was the inter-mediate of its parents in length, width and thickness. The germination percentage of the F1 hybrids was very high. (4) The Fl hybrids grew very vigorously, the sizes of their leaf, flower and pod etc. were much larger than thos of the parents. The hybrids were totaly sterile. (5) The chromosome number of the F1 plants was 2n=63, and at MI in their PMC's, 63I were most frequently observed. Judging from this, no homologous genomes seem to exist between the two parents.View full abstractDownload PDF (1174K) -
Tadao OINUMA, Toru YOSHIDA1974 Volume 24 Issue 5 Pages 211-216
Published: October 31, 1974
Released on J-STAGE: May 16, 2008
JOURNAL FREE ACCESSThree doubled haploid lines artificially derived from each of the burley tobacco varieties, Burley 21, Ky 10, and Harrow Velvet, were compared with the normal diploid lines in 1971. Some of the doubled haploid lines were gene-tically different from the normal diploid lines. At least, three out of the nine doubled hap-loid lines showed the reduced vigor, resulting in the lower yield than the normal diploids. However, none of the doubled haploid lines was higher than the normal diploids in yield. An experimental line, DH-6, derived from Ky 10 variety had an apparently higher leaf number than that of the parental variety. These results were ascertained by the experi-ments in the next year. From the comparison of clonally related doubled haploid lines, it was assumed that the genetic variation among the entries was due to the mutation occurred in haploid stage.View full abstractDownload PDF (813K) -
ToShio YAMAMOTO, Takuma GAMO1974 Volume 24 Issue 5 Pages 217-225
Published: October 31, 1974
Released on J-STAGE: May 16, 2008
JOURNAL FREE ACCESSEffects of different planes of feeding upon the several quantitative characters in silkworm larvae and effectiveness of selection for cocoon characters were studied. Using four strains of the silkworm, Bombyx mori, as material, cocoon weight and cocoon shell weight were selected successively for several generations with 15 and 20% selection intensities under three different planes of feeding : high (full feeding), medium (one half), and low (one third) for the 5th instar larvae as shown in Table 1. When silkworm larvae were reared on restricted feeding the variation in cocoon characters was increased proportionally to the degree of restriction (Table 2). When the larvae were reared on full feeding, both the cocoon weight and cocoon shell weight showed the largest values, while the coeffi-cients of variation were smaller than those on restricted feeding groups. The mean values and coefficient of variation of cocoon shell weight on three planes of nutrition were significantly differed (Table 3). When the feed was restricted the varia-tions in quantitative characters were increased by the competition among individual larvae, and in fact the variation was increased in proportion to the degree of restriction.View full abstractDownload PDF (1151K) -
Hiroko MORISHIMA, H.I. OKA1974 Volume 24 Issue 5 Pages 226-236
Published: October 31, 1974
Released on J-STAGE: May 16, 2008
JOURNAL FREE ACCESSVariations in logistic growth curve among rice varieties were investigated using dry-mat-ter weight data from the International Rice Adaptation Experiment. Two major trends of variation were detected, one represented by the developmental stage at which growth rate beco-mes maximum (variation betweeh early- and late-vigor types), and the other represented by the durability of high growth rate (between sustained- and dash-vigor types). These varia-tions were found to be controlled by varietal genotypes. Early vigor contributes to the production of many spikelets, while late vigor contributes to the growth after heading and filling the spikelets with grain. Sustained-vigor types gave more grain yield than dash-vigor types. The pattern of changes in these vigor types due to fertilizer application also appeared to be varietal characteristics.View full abstractDownload PDF (1218K) -
Isao TOJYO1974 Volume 24 Issue 5 Pages 237-240
Published: October 31, 1974
Released on J-STAGE: May 16, 2008
JOURNAL FREE ACCESSThe seed fertility of triplold mulbelry tlees derived from two ways was investigated. One group of triploids (A) was originated by crossing of artificialfy diploidized garnete cell (Ken-mochi, a diploid race) and normal pollen grain. (Kairyo-nezumigaeshi, a dip loid race) and the othel, (B) was originated by crossing of the autotetraploid of Kenmochi (4x) and Kairyo-nezumigaeshi (2x) Fertilities obtained under natural and artlflclal crosses varied between group (A) and (B), accord-ing to their different origins. Hign seed production and seed germination were observed in group (A) rather than group (B).View full abstractDownload PDF (565K) -
[in Japanese]1974 Volume 24 Issue 5 Pages 241-246
Published: October 31, 1974
Released on J-STAGE: May 16, 2008
JOURNAL FREE ACCESSDownload PDF (878K)
- |<
- <
- 1
- >
- >|