Yield and growth analysis have been applied to the results of an experiment comparing early and late sown peas. Yield analysis showed that in this experiment late sown peas had:

(i) fewer podding nodes per main stem,

(ii) fewer pods per podding node, and

(iii) a slower rate of increase in pod weight.

The physiological origins of these differences are discussed.

The first component is determined by the stage at which node production is terminated by the death of the apical bud.

The second is determined by morphogenetic factors at the apical meristem early in in the life of the plant, when (in the variety DSP) either a single or a double flowered raceme is initiated, and also during the harvesting period when some pods are lost from the lower-most flowering nodes.

The differences in the third component, the rate of increase in pod weight, could not be explained by conventional growth analysis. Pod growth rate was not a simple function of leaf area index.

It is suggested that the relationship between leaf area and pod growth rate is complicated by the existence of other sources of materials for pod growth such as stored products in the roots and stems, and photosynthesis by the fruit itself.

When both spring and winter varieties of field beans were entered in the same trial, sown on the same date (in the spring) and harvested on the same date, the seeds of spring varieties had mean crude protein contents which were higher than those of winter varieties by 3·1 ± 0·9% in the first trial, 2·8 ± 0·7% in the second trial, and 2·9 ± 0·3% in the third trial.

The effects of low and high seed rates on height, culm and panicle morphology of four oat cultivars grown in field trials in two growing seasons were investigated. Significant differences were detected between cultivars in the number of extended culm internodes, panicle whorls initiated, total height, length of panicle and individual internodes. Differences in seed rate had no effect on the number of culm internodes, but high seed rate significantly reduced the whorl number in the panicle, total plant height, length of panicle and the three upper internodes. The fourth internode remained unaffected, but the lowermost internode showed a relative length increase at high seed rate. The interaction of cultivar x seed rate was significant for total height, and for the length of the central internodes, but the length of the panicle was similarly affected in all cultivars.

Panicle conformation was markedly affected by seed rate; high population density caused a reduction in number of grain-bearing whorls, and reduced the number of spikelets and total grain weight per whorl, and 1000 grain weight particularly in the lowermost whorls. The percentage of husk in the grain was increased slightly at high seed rate. The effect of seed rate on culm and panicle morphology is discussed in relation to the development of stiffer-strawed oats.