The effect of sowing date and nitrogen on tillering patterns, survival and contribution of reproductive tillers to grain yield of standard and Mexican wheat cultivars were studied for two seasons.Maximum number of tillers/plant, 3-2-4-5, was observed after 40 and 27 days from sowing for 1970-1 and 1971-2 respectively. The number of ears/plant was 1-4 at the end of the growing season. Varieties differed in tillering, and LRN 10 and Giza 155 produced more reproductive tillers than Falchetto and Mexipak. Nitrogen application increased tillering efficiency, i.e. ratio of fertile to total tillers produced. Only 26 % of tillers appearing in the axil of the first true leaf (T x ) and 10 % of tillers in the axil of the second true leaf (T 2 ) survived to produce ears. The high mortality of tillers was attributed to high air temperature prevailing during the growth period (33 °C by day; 18 °C by night). Eared tillers did not die and were self supporting because of the photosynthesis by the ear.Grain weight/tiller was positively correlated with tiller dry weight at heading, r = 0-76-0-96. Main shoots contributed about 81 % of the total grain yield and 19% came from T 1 and T 2 tillers. TNTRODTTCrTfW*^e e^e c t s °^ sowing date and nitrogen application were included. In wheat, as well as in other cereals, the number of fertile tillers at harvest is determined by produc-MATERIALS AND METHODS tion and death of tillers. A large proportion of tillers in wheat is unreproductive, and early formed Four wheat (Triticum aestivum L.) cultivars tillers have a greater chance of surviving and (Table 1) were grown in a factorial experiment with produce larger ears (Bunting & Drennan, 1966). four replicates over the seasons 1970 -1 and 1971 -2 Rawson (1971 reported that true leaf tillers were at Hudeiba Research Farm in the Northern promore efficient in grain production than coleoptile vince of the Sudan. node tillers and prophyll tillers. Cannell (1969a) The varieties were planted at two sowing dates, studied tiller production of barley and found that 19 November and 10 December, at four nitrogen tillers in the axil of the first true leaf, which is levels, namely 0 (N o ), 48 (NJ, 96 (N 2 ) and 144 (N 3 ) equivalent to tillers in the axil of the first true leaf kg N/ha in the form of urea applied at sowing. (T t ) in this study, produced more grain than the Seed rate was 85 kg/ha hand-drilled in rows 20 cm coleoptile node tillers.apart. Each plot was 9-2 m long and 5-8 m wide Donald (1968) suggested that a single-shoot and only 19-2 m 2 (7-0 x 2-8) was used for final ideotype is a desirable character in wheat varieties, harvest. The experiment was irrigated every 10-14 but Simpson (1968) found that the high grain yield days and weeded twice, of the Mexican semi-dwarf wheats was attributable to their capacity for high tiller production.RESULTS The objectives of this study were to determine tillering patterns and survival, and the contribution Tiller survival of reproductive tillers to grain yield of standardThe number of live shoots/plan...

SummaryThe growth and yield of four varieties of field beans were studied in field experiments in 1967 and 1968.Seed yield of the varieties Albyn Tick, Herz Freya, Blue Rock and Maris Bead were similar (averaging 6600 kg/ha) in 1967, but in 1968 Albyn Tick and Herz Freya (averaging 6400 kg/ha) outyielded Maris Bead (5700 kg/ha). Yield in both seasons were substantially more than the national average yields for Britain (about 3000 kg/ha). In 1968, yields were 40% greater at 57 plants/m2 (7100 kg/ha) than at 36 plants/m2 (5100 kg/ha).Yield was closely correlated with number of pods/plant. The number of pods/node regulated this rather more than the numbers of nodes forming pods. Mean seed weight and seed number/pod varied little between plant densities but variety means were significantly different.Maximum numbers of immature pods were present in late June. By mid-July 35% of the immature pods had shed, mainly from the middle and top of the range of podbearing nodes.

SummaryExperiments were conducted at Gezira Research Station during the 1964 and 1965 seasons to determine the effect of time and number of weedings on pod yield of Ashford groundnuts.Natural stands of annual weeds, mainlyIpomoea cordofanaandRhynchosia memnonia, reduced the pod yield by an average of 80%. Results showed that groundnuts must be weeded at least once after the first 30 days from sowing. Groundnut pod yield was increased from 986 kg/ha in the unweeded plots to 4690 kg/ha in the plots weeded 30 and 60 days after sowing. Three weedings, i. e. 15, 30 and 45 days from sowing, yielded less than 30 and 60 days from sowing because weeding stopped too soon. For practical purposes weeding at 30 and 60 days only was adequate.Number of pods per plant was the most important factor determining yield. Maximum pod yield was obtained from 15–20 pods per plant, and the earlier the 20 flowers produced, the higher was the pod yield.Weeds decreased number of branches per plant and consequently number of pods per plant. Weight of 1000 seeds, shelling percentage and harvest index was also affected by weeds.Ipomoea cordofanawas the most noxious weed because it emerged about the same time as the groundnut plants and also the seeds germinated throughout the growing season.

SummaryLeaf burn and gradual death were the characteristic symptoms of injury in P. vulgaris sown on a sodic soil. Plant growth, total leaf area per plant, number of stomata and epidermal cells per unit leaf area, and relative water content were drastically reduced in injured plants; these were associated with large sodium accumulation in the shoot resulting in cation imbalance.

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