Serradella (Ornithopus sp.): maturity range and hard seed studies of some strains of five species

Abstract

Two experiments are described which measured the maturity range and the softening of hard seeds of several species and strains of serradella (Ornithopus sp.) grown in field experiments near Esperance, Western Australia. Softening of hard seeds was measured in a diurnal 15/60¦C alternating temperature oven (laboratory oven) and from germination tests of samples collected periodically during summer from the field experiments (field test). Within O. compressus, there was a difference of about 30 days between strains, in time from sowing to appearance of the first flowers. The earliest flowering strains of the other species were included in the experiments; none commenced to flower as early as the earliest flowering O. compressus strains. When stored in the laboratory oven, the rate of softening of podded serradella seed varied markedly depending on species and strain, particularly for strains of O. compressus. Compared to naked (dehulled) seed, podded seeds of O. compressus and O. pinnatus softened in the laboratory oven at a much slower rate. The numbers of soft seeds were between 35 and 75% less, depending on strain and year. However, for O. isthmocarpus and O. perpusillus, the rate of softening was similar for both dehulled and podded seed. Irrespective of pod treatment, O. sativus was very soft-seeded. Within the bounds of the data, compared to the field test, the numbers of soft seeds counted for the laboratory oven tests were generally higher. Qualitatively the trends were similar for both methods.