ALBERT

Description: SUMMARYExperiments on outdoor bush tomatoes cv. Sleaford Abundance were conducted during 3 years to compare seedling establishment from fluid-sown pre-germinated seeds with that from conventionally sown dry seeds and to compare the effects on ripening and yields of these establishment methods with transplanting. Fluid-sown pre-germinated seeds emerged about 15 days earlier than conventionally sown dry seeds from sowings made in late April (mean soil temperature at seed depth from sowing to emergence ranged from 9 to 11.5 °C) and about 6 days earlier from sowings made in mid-May (mean soil temperature ranged from 12 to 15 °C). The percentage seedling emergence from pregerminated fluid-sown seeds was, on average, 57% from the earlier sowings and 65% from the later sowings, 34 and 24% higher, respectively, than from dry seeds sown conventionally. Plants from fluid-sown pre-germinated seeds were about 50% heavier than those from dry seeds at all stages of growth up to flowering. Crops established by fluidsowing started to ripen 7 days earlier than those established from dry seeds, when averaged over sowing dates and years. Yields of ripe marketable fruit 〉 35 mm in. size from crops established from pre-germinated seeds were 35·2 t/ha, averaged over sowing and planting dates, 37% higher than from dry seeds though 51% lower than from transplants. In the two years with good growing seasons crops fluid sown in late April gave as good yields as those transplanted in late May and early June, after the last frosts, though in the cool wet year yields from fluid-sown crops were considerably lower than those from transplanted crops. Yields of ripe, marketable fruit from ‘bare-root’ plants raised from pre-germinated seeds in unheated Dutch-light structures were, on average, 48·5 t/ha, 25% higher than from plants raised in soil blocks in a heated glasshouse.

Description: SummaryIn field experiments made over 3 years Pentland Crown and Majestic gave, in general, higher total and dry matter yields from plots given no supplementary water and protected from rainfall throughout growth than King Edward or Maris Piper. However, on plots kept at or near to field capacity all varieties gave similar yields. Pentland Crown and Majestic were deeper rooting than the other two varieties at the time of tuber formation (when the production of new roots ceased) but the differences in rooting depth (ca. 100 mm) between the varieties were small. Except for the top 150 mm of soil, differences in water extraction between the varieties throughout the profile were also small. Neither these differences in water extraction nor the differences in rooting depth could be related consistently to the differences in varietal yield response between ‘wet’ and ‘dry’ plots.

Description: SUMMARYData are presented relating various stages of growth of field-grown bush tomatoes cv. Sleaford Abundance established from dry and pre-germinated seeds and from transplants to accumulated day-degrees. In general, Ontario units predicted the dates of 50% flowering, of the first harvest and the date when 37·5 t/ha of ripe fruit had been picked, more accurately than day-degrees above 10 °C or calendar days. The number of Ontario units from sowing to 50% flowering for dry and pre-germinated seeds were 956 ± 35 and 871 ± 85, respectively. The corresponding figures from sowing to first harvest were 1958 ± 59 and 1867 ± 85. For transplanted crops the number of Ontario units from planting to 50 % flowering and from planting to first harvest were 322 ± 62 and 1352 ± 133, respectively. For transplanted crops the number of Ontario units required to give a yield of ripe fruit of 37·5 t/ha (the minimum level currently necessary on economic grounds for tomatoes for processing) was 1937 ± 112. Using this figure in conjunction with long-term meteorological records it was estimated that crops established from transplants at East Mailing, Kent (latitude 51° N), would fail to give yields of ripe fruit of 37·5 t/ha by late September on only 1–6 occasions in 100 whereas at Wellesbourne, Warwickshire (52° N) and Warsop, Nottinghamshire (53° N) crops would fail to reach this yield on 13–53 occasions in 100. Crops established directly from seeds would fail to give this yield on more than 50 occasions in 100 at all three sites.

Description: In recent studies of variability in carrot (Umlauf, 1978; Dowker & Gray, 1985) it was concluded that increasing the genetic uniformity of the seed populations did not bring about a detectable reduction in the variability in embryo sizes, the spread of emergence or seedling weight. In these experiments, however, only broad comparisons were possible since the seed sources used were not obtained from crops grown under identical cultural conditions or harvested at the same stage of maturity, both of which affect variability in the subsequent crop (Gray & Steckel, 1983). The purpose of the present experiment was to examine the influence on variability of the greater genetic uniformity of an F1-hybrid compared with an open-pollinated cultivar, when both were sown under identical conditions.