SummaryThe winter-heading cauliflower varieties St Thomas, St Gwithian, St Agnes, Janavon, St Hilary, St Buryan, BB74605, St David and St Keverne were grown at Trefloyne, Tenby for 3 years from 1977 to 1980. Plants of all varieties were sampled periodically to determine the rate of curd expansion, the final number of leaves, the time of curd initiation, and the distribution of dry matter within the plant.The patterns of development of leaf area were similar in all varieties. Dry-matter distribution was similar for all varieties except for root growth; later-maturing varieties had a greater dry weight of root and a higher proportion of the total dry matter as root, than early varieties. Early rates of curd growth declined with later-maturing varieties and it is suggested that there may be a relationship between the time of curd initiation, root growth and the rate of curd growth.The mean total number of leaves formed before curd initiation varied from 49 to 102 depending on the variety and year. The earliest varieties St Thomas and St Gwithian took co. 120 days to reach 50% curd initiation and matured in 6–7 months from sowing while the late variety St Keverne took over 200 days to reach 50% initiation and more than 11 months to mature. The time interval between 50% initiation and 50% maturity increased with later-maturing varieties but on the basis of accumulated day degrees > 6 °C it declined with later varieties. The latter also matured more uniformly than earlier varieties when using an accumulated day-degree scale > 6 °C as a time scale.The results suggest that the low temperature threshold below which curd induction occurs may vary with variety. There was also evidence that the base temperature for curd growth is lower with later-maturing varieties.
Root Growth and Dry Matter Distribution of Soybean as Affected by Phosphorus Stress, Nodulation, and Nitrogen Source
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