24 research outputs found
Influence of position of panicle on seed and seedling characteristics of rice (Oryza sativa L)
The characteristics of seeds obtained from primary, secondary and tertiary branches of panicles in four varieties. of Indica rice (Oryza sativa) were evaluated. The germination patterns and viability of procured seed and the vigour and characteristics of seedlings developed from these seeds were also studied. The characteristics of seeds of the three branch types ofthe four varieties and their seedlings were similar. In contrast, marked differences were observed between the seeds obtained from the three types of branches. Seeds of primary branches of the panicle had a greater 100-seed weight. The lowest weight was observed in seeds from tertiary branches. This difference was principally due to the heavier endosperm of the seeds of primary branches, which in turn increased the endosperm:embryo ratios. The viability and germinability ofthe three categories ofseed were similar to those ofseed characteristics. Seed from primary branches of the panicle had a higher viability. The vigour of seedlings from these seeds was also greater. Differences in growth of seedlings from the these seeds was also greater. Differences in growth ofseedlings from the three branches of the rice
panicle were similar in terms of characteristics and viability of seeds. The study revealed that seedlings from seeds of primary branches manifested superior growth because of better seed characteristics. Some practical implications of the study are discussed
Response of selected tropical grasses to irrigation with brackish water
Agricultural development programmes in the sandy regions of the dry zone of Sri Lanka envisage the establishment
of suitable fodder for livestock under irrigation programmes using brackish underground water. A study
evaluated the response of three popular tropical grasses and the natural species to irrigation with brackish water
having conductivities ranging from 0.5-6.0 ms. cm, when established in a sandy soil. The study was carried out
for 6-7 months, with regular irrigation to correspond to the dry season. Growth of all three species was affected by
increasing conductivity of water. Brachiaria mutica was affected to the greatest extent. Yields of Paspalum
dilatatum were reduced to a lesser extent with increasing brackishness of water. Panicum maximum produced
the highest yield and provided a significant quantity offodder in all treatments. However, the introduced species
outyielded the natural species with the exception of Brachiaria at the higher levels of conductivity. The data
illustrated the effect of brackishness on the yielding ability of the selected species. The practical significance of the
study in terms ofpossible uses of these species in growing grasses under irrigation in the sandy tracts for herbage
production in the dry season is presented
Response of french bean (Phaseolus vulgaris L.) to rate and ratio of potassium fertilizer application
A field study was undertaken to evaluate the effect of potassium fertilizer, when applied in different ratios, as a
basal or top dressing on vegetative growth, immature pod and seed yield of French bean as well as seed quality for
planting purpose determined by germination before and after controlled deterioration. The ratios of fertilizer
application at a given rate of 100:0,50: or 0:100, were added at planting (basal) or at flowering (R1 stage - top
dressing). Establishment of French bean was not affected by potassium. In contrast, vegetative growth and most
yield components increased significantly with up to 100 kg K20 per ha. Application of a given rate only at planting
(100:0) enhanced vegetative growth compared with a split rate. Application at flowering alone (0: 100) reduced all
measured parameters, confirming the requirement of potassium at planting. Yields of immature pods harvested for
vegetable purposes were not significantly increased by the two applications in the ratio of 50:50 (basal: top
dressing). Seed quality determined by germination before and after controlled deterioration was also affected and
split applications of 100 kg K20 in the ratio of 50:50 increased germinability
Influence of seed ripeness, sarcotesta, drying and storage on germinability of papaya (Carica papaya L.) seed
Papaya (Carica papaya L.) is a popular tropical fruit which is propagated by seed. However, germination and
the procurement of good seedlings are difficult in this species due to the nature of the seed. Thus a series of studies
to evaluate the influence of fruit maturity, sarcotesta and drying on germination and production of healthy
seedlings was carried out. The characteristics of papaya seed change with fruit maturity. Speed of germination
increases with fruit maturity. Thus, the best seed for germination and for the the procurement of healthy seedlings
is obtained from ripe or over-ripe fruits. The presence of the sarcotesta reduces germination and increases the
number of abnormal seedlings. Incorporation of the sarcotesta in the germination medium of papaya or rice seeds
did not inhibit their germination. This suggests that inhibition is caused by the intact sarcotesta rather than
inhibitors derived from it. Drying papaya seeds under shade and ambient temperature maintained germinability
to a greater degree than when seeds were desiccated in ovens. The reduction of seed moisture below 10% reduced
germination significantly, indicating an intermediate behaviour pattern for papaya seeds in contrast to orthodox
or recalcitrant seeds
Crop diversification strategies for minor irrigation schemes: Proceedings of the workshop organized by the Irrigation Research Management Unit, Irrigation Department and the Sri Lanka National Program, International Irrigation Management Institute, held at the Irrigation Department, Colombo, Sri Lanka on 20 February 1996
Irrigation programs / Irrigation management / Small scale systems / Crops / Diversification / Rice / Cropping systems / Constraints / Social aspects / Economic aspects / Field crops / Crop production / Labor / Farmers' attitudes / Water management / Groundwater / Sri Lanka