SUCROSE AND NITROGEN EFFECTS ON GREENNESS, HEAD PARAMETERS AND FLOWERING OF FOUR LINES OF CABBAGE

Abstract

A study was carried out to determine whether increasing the sucrose concentration to seedlings in vitro and subsequently increasing N supply to plants in soil can affect head parameters or greenness which may lead to flower induction in cabbage. A further aim was to find out whether there is a relation between SPAD meter values for greenness and total chlorophyll of four cabbage varieties under study. Sterilized cabbage seeds were cultured individually in glass jars with heat sterilized agar medium containing 0 or 3 % sucrose. Plants generated were raised in 23 em pots and a total of 0 or 7 g N per pot was applied as a top dressing to the plants. In a separate experiment, after greenness had been measuredfrom leaves of each of the four varieties, I cm leaf discs were cut from the exact points where the measurements of greenness were taken and total chlorophyll determinedfor each disc. Sucrose and N increased the stem height at flowering independently and the combined effect of 3 % sucrose and 7 g N promoted early flowering of 'HRI 006556' as compared to when each.treatment was applied alone. Supply of7 g N caused head splitting of three varieties and reduced the solidity of 'KK Cross '. Variety, sucrose and N affected the SPAD readings. There were significant positive relationships between SPAD meter value for greenness and the total chlorophyll for data pooledfrom all the four cabbage varieties, however there were variety differences in the relationship that required the development of a separate regression equationfor each variety of cabbage for effective prediction of total chlorophyll from SPAD meter readings.