S U M M A R Y Field trials are described in which the seed yield response of row-sown sesame to increasing plant population was examined, and in which row-sowing was compared with broadcasting at different seed rates. Maximum yields were obtained at an intended 200 to 250 X 10' plants ha" 1 but yields were not greatly affected by a wider range of populations. Broadcasting, the normal local practice, gave yields slightly higher than those from rows 50 cm apart, the unthinned rate of 800 X 10 3 viable seeds sown ha" 1 yielded as well as treatments thinned to the optimum population, and double this seed rate, unthinned, gave the lowest yields, especially in rows.RESUMEN-SUMARIO Se describen experimentos de campo en los cuales, se examina la respuesta en rendimientos de semilla de sesamo sembrada en hileras, en relacion al incremento en el numero de plantas, y en los cuales la siembra en hileras es comparada con la siembra al voleo a diferentes tasas de semilla. Los rendimientos maximos se obtuvieron a la tasa de 200 a 250 X 10 3 plantas ha" 1 , sin embargo los rendimientos no fueron significativamente afectados por un rango mas amplio en la poblacion de plantas. Siembra al voleo, la practica local normal, entrego rendimientos un poco mas altos que aquellos en hileras de 50 cm de separation, la tasa de 800 X 10 s de semillas posible de sembrar ha" 1 , sin raleo, entrego rendimientos semejantes al del tratamiento de raleo hasta una poblacion de plantas optima, y cuando esta tasa de semillas fue doblada -sin raleo -entrego los rendimientos mas bajos, especialmente en hileras.

S U M M A R YLines partially-isogenic for the dejiciens (VV) and two-rowed ( W) barley ear types were developed in the genetic background of cv. Kym, for comparisons of ear development and yield components.The suppression of lateral floret growth by the V allele during pre-anthesis ear development occurred at a relatively late stage and only occasionally was median floret survival enhanced in the deficiens line. The final size of lateral florets in both dejciens and normal ear types appeared to be largely governed by assimilate supply. At anthesis, the lateral florets comprised about 10% of the dry matter of normal ears, whereas in the dejciens ears the median florets were correspondingly heavier. After anthesis, grain growth in the dejiciens line was slower than in the normal line, although final grain weight was not affected.In another experiment the V allele occasionally increased the number of grains per ear, but consistently decreased the weight per grain. In drilled plot trials, the mean yield of the deficiens line was 8% lower than the normal. Excision of lateral florets at anthesis showed that photosynthesis in these organs did not contribute to the yield advantage of the normal ear type.It is suggested that the inferior performance of the deficiens type was attributable to the greater physical constriction of endosperm expansion imposed by the development of thicker, more rigid, palea and lemma tissues.