摘要:

Uniformity data for eight different crops were studied with the object of making comparisons of the efficiency of Incomplete and Randomized Block methods. Altogether 26 different comparisons were made.In general the Incomplete Block method gives increases in efficiency, such increases being partially correlated with soil heterogeneity. If the field is very uniform there may be a loss in efficiency but this is rather unlikely on the average field and with careful planning of the experiment. The increases in efficiency due to the use of Incomplete Block methods would appear to vary on the average from 20 to 50%. In view of the greater adaptability of these methods to irregularly shaped fields, in addition to greater efficiency, their use can be generally recommended.The relative efficiency of Incomplete and Complete Block methods was studied in relation to the size and shape of plots and blocks. The former method gives the greatest gains in efficiency when the Incomplete Blocks are nearly square and are made up of long narrow plots.

ISSN:1923-4287    

DOI:10.1139/cjr37c-020

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

The precision of the malting test made in equipment already described (Can. J. Research, C, 15: 204–216. 1937) was studied by making four batches of malt each of which contained duplicate malts made by eight treatments representing the combination of steeping for 48 or 60 hr., maintaining the germination chamber at 53° or 54.5° F., and kilning for 36 hr. at 100° to 175° F. or for 52 hr. at 90° to 165° F. The standard errors of duplicate tests made in the same and in different batches were found to be: extract, 0.08 and 0.09%; moisture, 0.04 and 0.05%; color, 0.04 and 0.05 units; diastatic power 1.0 and 2.8° L.; permanently soluble nitrogen as percentage of wort solids, 0.01 and 0.02%; malting loss 0.06 and 0.29%; and sprouts, 0.06 and 0.18%.On the average, increasing the time of steeping decreased extract by 0.08%; but increased diastatic power by 3.2° L., permanently soluble nitrogen by 0.05%, malting loss by 0.98% and sprouts by 0.44%. Increasing the temperature of the germination chamber increased diastatic power by 4.2° L., permanently soluble nitrogen by 0.04%, malting loss by 0.93%, and sprouts by 0.52%. Increasing the time and decreasing the temperature of kilning increased extract by 0.08% and diastatic power by 14.8° L. Statistical analyses show that the test is sufficiently precise to prove that these effects, though small, are significant.

ISSN:1923-4287    

DOI:10.1139/cjr37c-021

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

Following identification in 1932 of the Yellow-edge virus disease in England on the Royal Sovereign variety, "normal" plants of this variety from a clone minutely rogued for Yellow-edge were used at St. Catharines as indicators in a further study of virus as relating to certain Ontario varieties. Observations in the field and greenhouse, confined largely to the varieties Parson's Beauty, Premier (Howard 17), Forward and Glen Mary, showed that symptoms analogous to those of Yellow-edge in England and sufficiently defined to permit of diagnosis were apparent only on Parson's Beauty and Forward, and then only for a limited period early in the growing season. In the 1933–35 transmission experiments (by runner grafting), symptoms macroscopically indistinguishable from those of typical Yellow-edge-infected plants in England were induced on Royal Sovereign from the local varieties Glen Mary, Parson's Beauty and Premier, which possess markedly the symptomless-carrier capacity. Of special interest was the deterioration of Premier components in certain graft series, the evidence suggesting reciprocal infection between test and indicator plants.Finally, parallel experiments at the East Mailing Station in 1935–36 provided supplementary data as follows: (1) Of the two parentFragariaspecies common to commercial varieties in North America and in England,F.chiloensiswas found to be a symptomless-carrier of Yellow-edge with a high order of resistance, andF.virginiana, in complete contrast, exhibited symptoms with extreme readiness together with high susceptibility, thus providing some explanation of the observed wide range of varietal reaction to disease of the Yellow-edge type. (2) A large proportion of the clone of Royal Sovereign plants used as "normal" indicators in the recent series of experiments, was found to be infected with a distinct virus of the "Crinkle" type, thus providing explanation of an observed reciprocal reaction in certain series with the Premier variety.

ISSN:1923-4287    

DOI:10.1139/cjr37c-022

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

The somatic chromosome numbers of 20 species ofPoawere determined. The basic chromosome number for the genus was found to be seven. The species arranged themselves in a polyploid series from diploid to dodecaploid, tetraploids and hexaploids being the most numerous. Three aneuploid species possessed chromosome numbers suggestive of a nonaploid origin. Polymorphism was found to be present inP.compressaL.,P.palustrisL. andP.nemoralisL. All species examined conformed to the long chromosome type common to the subfamily, Pooideae. The spindle fibre attachment for the chromosomes in the various species ideograms was found to be regularly median or submedian.The chromosome variability and the mode of seed production were examined inPoa pratensisL., using selected, uniform strains, indigenous plants and plants grown from commercial seed. The somatic chromosome number was found to range from 50 to 87 ± 1, 10 of the 19 plants examined possessing aneuploid numbers. The selected strains possessed the same chromosome number for both plants examined, while in the other material the number was variable. A study of meiosis in the P.M.C. showed the selected strains to vary from regular behavior to an irregularity of 3.9 unpaired univalents per cell. All strains possessed large percentages of morphologically good pollen which germinated actively on the stigmas. Reduction was observed in the E.M.C. of the selected strains and a study of the course of embryological development showed no irregularities which might lead to aposporous reproduction. A high frequency of polyembryony was observed which was correlated to the degree of irregularity at meiosis. A theory is advanced to explain how constant aneuploid numbers may be maintained in sexually reproduced strains.

ISSN:1923-4287    

DOI:10.1139/cjr37c-023

出版商:NRC Research Press    

年代:1937

数据来源: NRC