Relation of seed weight to grain yields in oats, Avena sativa L.
SummaryWe measured yielding ability and weight per 100 seeds in 7 populations of oat lines, each derived from a different cross. The association between these two traits was curvilinear, with maximum yields occurring when 100-seed weights were between 2.75 and 3.10 g.In a simulated selection experiment conducted on a bulk population of 150 oat lines (i.e. only lines with seed weight between 2.75 and 3.10 g per 100 seeds were saved), the proportion of superior yielding lines was increased from 16% in the original to 32% in the new one. In the 100-seed weight class below 2.75 g, the proportion of high yielding lines was only 5%.
An evaluation of an index method of selection for high yield in turnip rape, Brassica campestris L. ssp. oleiferaMetzg
SummarySubstantial variation in yield, its primary components and several vegetative characters which influence yield was observed among a series of families drawn at random from a low erucic acid variety of turnip rape. A sib analysis of family means showed all characters to have relatively high heritabilities, although yield was, together with seed weight and specific leaf weight, in a group having the lowest values.Several characters, including flowering time, leaf area and leaf weight, had appreciably higher heritabilities than yield, however, none appeared to be a suitable alternative criterion for selection as the expected correlated responses to selection for these characters were lower than the direct response to selection for yield. The expected genetic advance in yield from the simultaneous selection for a number of these characters using a selection index technique, was significantly greater than that expected from selection for yield alone. Selection indices based either on yield components or vegetative characters were, at best, only as efficient as selecting directly for yield. Several indices including measurements of both yield components and vegetative characters were, however, expected to facilitate a greater rate of advance in yield than direct selection.The practical value of such indices in improving rapeseed yields in Western Australia was discussed with reference to the additional costs involved in their use and their accuracy in environments where genotype x environment interactions are likely to be high.
A slowly rotating coil system for AC field measurements of Fermilab Booster correctors
A method for measurement of rapidly changing magnetic fields has been developed and applied to the testing of new room temperature corrector packages designed for the Fermilab Booster Synchrotron. The method is based on fast digitization of a slowly rotating tangential coil probe, with analysis combining the measured coil voltages across a set of successive magnet current cycles. This paper presents results on the field quality measured for the normal and skew dipole, quadrupole, and sextupole elements in several of these corrector packages.