July Sowing Research Articles

異なる播種時期における抽だい特性に基づくトルコギキョウのロゼット性の品種分類

Eustoma grandiflorumseedlings become rosetted under high temperature conditions. This characteristic varies among cultivars. To classify 241Eustomacultivars based on their rosetting characteristics, the bolting rates were checked weekly after sowing in May, June or July. When seeds were sown in May, the bolting rate was generally higher, but in June sowing, bolting rates ranged from high to low values. The bolting rate in July sowing was the lowest. Abnormal bolting was observed in all of the three sowing months. In evaluating bolting rate, the bolting rate of abnormally bolted seedlings was multiplied by 0.5 and that of rosetted ones was regarded as 0. Based on the calculated rosette index using this evaluated bolting rate, we ranked all the 241 cultivars as A-E (rosette index : A<20, 20≤B<40, 40≤C<60, 60≤D<80 and 80≤E) . As a result, 17, 35, 122, 56 and 11 cultivars were ranked as A, B, C, D and E, respectively.

Effects of sowing time and nitrogen fertiliser on canola and wheat, and nitrogen fertiliser on Indian mustard. II. Nitrogen concentrations, N accumulation, and N fertiliser use efficiency

Canola, Indian mustard, and wheat were grown at Ariah Park and Cowra (canola only) in the cropping belt of New South Wales, Australia, to determine the effects of sowing time (canola and wheat) and nitrogen (N) fertiliser on N concentrations and N accumulation in shoots, N fertiliser use-efficiency, and N removal in grain of the crops. Concentrations of N in shoots of all crops decreased during the season, irrespective of sowing time or N fertiliser rate. Late sowing decreased N accumulation by 55% and 40% for canola and wheat, respectively, at Ariah Park, and by 50% for canola at Cowra, but increased canola and wheat grain N (protein) concentrations more than the applied N. All crops accumulated most of their N before anthesis, and there was little N accumulation after the end of flowering; however, sowing canola late increased the proportion of N accumulated during flowering. Indices of N fertiliser use efficiency were reduced by sowing late, but N use efficiencies of the oilseeds at each sowing time were similar to values for wheat after accounting for differences in the biosynthetic costs of grain and straw production. Removal of N in canola grain from an April sowing was 35% greater than N removal by wheat grain sown at the same time, but was similar for both crops from late May and July sowings. Consequently, more N fertiliser should be applied to canola than wheat to obtain high grain yields when both crops are sown early in the season. It was concluded that sowing early was essential to achieve high N use efficiency, reduce potential losses of N, and maximise economic returns from N fertiliser.

The effect of sowing date on the growth and production of Lunaria annua in Southern England

Lunaria annua L. is a biennial which has a cold temperature vernalisation requirement. It is widely grown in many temperate countries as an ornamental flower. Interest in the species as an industrial crop has developed from the discovery that it has a seed oil content of 30–40% which contains high levels of erucic (C22.1) and nervonic (C24) acids. An experiment was carried out over the period 1993–1995 to investigate the production potential of the cultivars Kings Crown Purple and White and Monnaie du Pape and the effect of sowing in June, July or August. Plant establishment was between 30 and 40% of seed sown, considerable plant loss occurred over the growing period. Plants sown in June and July flowered early in the following April of both years. Flowering of August sown plants was variable, in 1994 less than 5% flowered, but in 1995 the majority flowered. Albugo candida was recorded on leaves and pods in both years. Seed yield from June and July sowings averaged 2.11 t ha −1 in 1994 and 1.25 t ha −1 in 1995. The purple flowered types (Kings Crown Purple and Monnaie du Pape) out-yielded the white flowered type in both years. Yield differences between June and July sowing dates were small. In 1994 August sown plants did not produce a harvestable yield; in 1995 their yield was significantly lower than other sowing dates. Seed oil and its composition of erucic and nervonic acid averaged 29.9, 50.2 and 22.6%; between-year effects were greater than cultivar and sowing date effects.

Late autumn and early winter sowings increase survival of native plant species in rehabilitated mine sites in the Western Australian Kwongan

ABSTRACT Optimum sowing times were examined for 17 native plant species in rehabilitated mineral sands mine sites at Eneabba in the Western Australian Kwongan (115°20'E, 29°30'S) from 1982 to 1988. In 1987 and 1988 a superphosphate fertiliser was applied to half of the treatment plots. From 1982-1986, best survival was recorded for May, June and July sowings. However, seedlings from sowings in February, March and April were taller and showed a larger number of leaves than seedlings which resulted from sowings during the later months of the year. For most species survival greatly varied with the year of sowing and was likely affected by several factors, among them low rain fall and high temperatures during summer, and predation. Establishment of seedlings benefited from the application of superphosphate as fertiliser only for one of seven species (Neurachne alopecuroidea).

Agronomy and phenology of “companion plants” of potential for enhancement of insect biological control

Abstract Many insects which are useful as biocontrol agents feed on pollen and nectar as adults. Nectar and pollen sources (as “companion plants) can be grown around or within crops to increase the density and diversity of predators and parasites. Plants vary in their suitability for such uses, however, and in this work, three cultivars of Coriandrum, two of Phacelia, and one each of Anethum and Fagopyrum were compared with respect to their sowing‐to‐flowering times, and susceptibility to low temperatures in Canterbury, New Zealand. There were large differences between cultivars with respect to sowing‐to‐flowering times. The time to flowering was the greatest with autumn sowings and Anethum was the most noticeably delayed. Fagopyrum failed to flower from March to July sowings, indicating a sensitivity to low temperatures or frosts; however, it had the shortest sowing‐to‐flowering period of all plants tested. The possibility of assessing other Fagopyrum cultivars for their tolerance to low temperatures an...

Effects of soil temperature on hollowness in Japanese radish ( Raphanus sativus L. cv. ‘Gensuke’)

To examine the effect of high soil temperature on the development of hollowing in the root of radish, seeds were sown in the field on 27 May, 10 July and 16 August 1992. Plants of the July sowing were subjected to soil temperatures above 32 °C during the middle of the growth period. Root weight was reduced and hollowness occurred in roots from the July sowing. Roots of the July sowing had the greatest concentration of vessels in the central region. Lignin formed in walls surrounding the central cavity only in roots of the July sowing. In a second experiment, seeds were sown on 30 April 1991, in plastic pots with heating cables to increase soil temperature. Heating from the 16th day after sowing (DAS) to the 30th DAS and from the 31st to the 45th DAS slowed root growth, and produced some hollow cavities, caused more vessels to form in the central area, and promoted lignification near the central cavity. In contrast, heating from the 10th to the 15th DAS or from the 46th to the 60th DAS produced roots with no hollow cavities, and resulted in the production of a smaller number of vessels in the central region of the root. The heating during these periods had no effect on lignin formation. In conclusion, a large hollow cavity develops in the central region of the root as a result of active lignin formation in the surrounding cells induced by heating in the middle of the growth period.

Growth and yield response of barley and chickpea to water stress under three environments in southeast Queensland. II. Root growth and soil water extraction pattern

Root growth and water extraction of two barley cultivars, Corvette (early maturing), Triumph (late maturing) and one cultivar of chickpea (Amethyst at Redland Bay and Borwen at Hermitage) were compared under three environments: April sowing and July sowing at Redland Bay and June sowing at Hermitage Research Station, south-east Queensland. This work was designed to explain differences in dry matter production in terms of root growth and water uptake during the crop growth, which relied only on stored soil moisture. In the April sowing where all crops grew well during the early stages of growth, decline in soil water with time for the whole profile was similar among all crops. In the winter sowings (June, July), total water use was less in chickpea than in barley, particularly during early stages when chickpea growth was poor. Water extraction patterns of two barley cultivars were similar in all experiments, though the late-maturing Triumph extracted slightly more water than early maturing Corvette towards maturity. Water extraction front velocities of the three crops were similar in each experiment. At Redland Bay, the water extraction front velocities varied from 1.4 to 1.6 cm day-1 in the April sowing and 2.3 to 2.4 cm day-1 in the July sowing, while they varied from 2.0 to 2.3 cm day-1 at Hermitage. However, descent of the water extraction front commenced later in chickpea than in barley when sown in winter months, and this resulted in lower total water use in chickpea, particularly at Hermitage. In both sowings at Redland Bay total root length increased rapidly to about 60 days after sowing in barley, whereas the increase was slower in chickpea. Root length density was high in the upper soil layers, and this was associated with high extractable soil water. In deeper layers both root length density and extractable soil water decreased. For a given root length density chickpea extracted more water than barley. These results indicate that the differences in root growth and water extraction by the two barley crops were rather small and were unlikely to be the reason for the differences in total dry matter production. Chickpea on the other hand appeared to be susceptible to low temperatures during early stages of growth, and this caused poor growth of both shoots and roots.

Seed and seedling studies of three Trifolium subterraneum var. brachycalycinum lines, in a predominantly summer rainfall environment

Field experiments were conducted in a predominantly summer rainfall environment to investigate burr burial, seed production, seed characteristics, seedling emergence and survival, and the effects of time of sowing on 3 Trifolium subterraneum var. brachycalycinum lines (cv. Clare and 2 local lines). Each line produced more surface than buried burrs; surface burrs were 59% (range 56-62%) of the total number of burrs recovered and produced 59% of the total seed number. Numbers of seeds per burr were similar for surface and buried burrs, however, buried seeds were 0.97 mg heavier (P&lt;0.05) than surface seeds. Storage for 5 months at 25/60�C decreased hardseed content of surface seed by 50% and buried seed by 70%. Surface and buried seeds stored at 25/25�C for 3 months prior to sowing in trays had a total emergence of &lt;10%, compared with 70% emergence for seeds stored at 25/60�C before sowing. These emergence differences reflected their levels of hardseededness. Numbers of seeds recovered from the soil were not significantly different among lines, declining from about 4200 seeds/m2 after initial seed set to 150 seeds/m2 by the following winter, a 97% decrease. Seed production in the second year increased seed reserves to about 8730 seeds/m2. With no further seed production, levels had declined by 93% in June 1990 and by 99% in May 1991. These data confirm the importance of annual seed production for persistence. Total seedling emergence in summer-autumn accounted for only 10% of the estimated seed production in each year. Seedling survival in summer-autumn 1988-89 was 92.7%, more than double the survival in 1989-90. The effect of sowing time on flowering was always significant, with time to first flower being highest (196 days) for the earliest sowing in March (P&lt;0.05), progressively decreasing (P&lt;0.05) to 108 days for the latest sowing in July. In March, April and May sowings, inflorescence numbers on the first day of flowering were similar at about 120/m2, but increased markedly (P&lt;0.05) for sowing in June or July. However, for the March and July sowings, number of inflorescences at the 9 November 1990 count, were lowest (P&lt;0.05). May or June sowings had the highest number of burrs and seeds (P&lt;0.05), indicating that these may be the best sowing times for maximum seed production in these Trifolium subterraneum var. brachycalycinum lines.

Influence of Seed Size and Growth Stage on Forage Sorghum‐sudangrass Hybrid cv. P988 Grown on Striga‐infested Soil

AbstractDelaying harvest of P988 from the boot stage to the maturity stage significantly reduced 1) forage greenchop yield of P988 grown on Striga‐ infested soil at 1st and 3rd harvest of July sowing and at 3rd harvest of October sowing, 2) root dry weight of P988 grown on Striga‐infested soil at 3rd harvest of July and October sowing, and 3) forage sucrose of P988 grown on Striga‐infested soil at 3rd harvest of July sowing and at 1st and 3rd harvest of October sowing. Reductions in forage greenchop yield of P988 with successive harvests were accelerated by Striga infestations. The root dry weight was significantly greater from P988 plants grown from small compared to large seed. Delaying harvest of P988 to the maturity stage was associated with significant increases in number of open Striga flowers at 1st and 2nd harvest from October planting and in Striga shoot dry weight at 1st harvest of July and 1st and 2nd harvest of October planting. These increases were positively correlated with forage sucrose of P988. Results suggest that optimal forage greenchop yield on Striga‐infested soil may be obtained from P988 plants grown from small seed and harvested at the boot stage.

RESPONSE OF GREEN GRAM (Vigna radita) TO SOWING DATES UNDER RAINFED CONDITIONS.

The experiment conducted at Gwalior showed that 13 July sowing and the variety ML-131 are the best for getting the high yield during kharif season in Northern Madhya Pradesh in respect of greengram.

Shoot apex fasciation in Sesamum indicum associated with mycoplasma‐like organisms

Shoot apex fasciation was observed in sesame crops in central Iraq. The symptoms included flattening of the shoot apex, shortened internodes, and intense proliferation of leaf and flower buds. Mycoplasma‐like organisms were detected by electron microscopy in sieve elements of fasciated plants but not in normal plants. Plants sown in July showed less fasciation than plants sown in June or May. Almost no fasciation occurred on plants grown inside insect‐proof cages, irrespective of their origin from seed of fasciated or normal plants. Insect‐borne and not seed‐borne transmission is therefore suggested.

Adaptation of sorghum/maize and sorghum/pearl millet intercrop systems to the toposequence land types in the North Sudanian zone of the west African Savanna

Cereal/cereal intercrop systems are commonly used by farmers in the higher-rainfall areas of the South Sudanian and Guinean savanna zones of West Africa. Towards the North Sudanian zone these systems become less common, because of a shorter rainy season with a more abrupt start and end. However, previous work on the responses of maize ( Zea mays), sorghum ( Sorghum bicolor), and pearl millet ( Pennisetum americanum) crops to the different toposequence land types indicated that crop mixtures of sorghum/millet for uplands and sorghum/maize for lowlands would be less prone to drought stress and waterlogging risks than would the respective sole crops. The present studies showed consistent intercropping advantages of at least 25% for sorghum/maize systems when both crops are sown at the same time. The relative advantages from this system were greatest for the uplands. Intercropping advantages were generally less for the sorghum/millet systems, and it proved essential to delay the millet sowing to prevent serious competition to the sorghum. Sorghum/millet intercropping provides a risk-reducing alternative to sole cropping, because sorghum plants lost during the common early droughts can be replaced by an early-maturing millet sown in July. However, because of the unpredictability of the early-season rainfall, sorghum/millet systems will be difficult to standardize; both the sowing date and the plant densities of the component crops may require adjustments each year in response to the starting date of the rains and the extent to which the sorghum has survived the early-season droughts.

Groundnut response to irrigation and sowing time on a deep loamy sand in a subtropical monsoon region

Abstract A 3-year field study was conducted to evaluate the individual and interactive effects of four irrigation schedules viz. 0, 1, 2 and 3 irrigations based on phenological growth stages and two times of sowing, viz. June and July, on groundnut ( Arachis hypogaea L.) grown on a deep, well drained, loamy sand in northwest India. The crop sown around June 20 with a pre-sowing irrigation made greater use of the profile-stored water and seasonal rain, to produce, on average, 600 kg ha −1 (34%) higher pod yield than the traditional practice of sowing the crop in July with the onset of monsoon rain. The yield advantage of the June over the July sowing was greater in the unirrigated crop (82%) than the crop irrigated once at pegging (19%) or twice at pegging and pod formation (40%). Compared with no irrigation, one irrigation at the pegging stage and two irrigations at pegging and pod formation stages resulted in mean pod yield increases of 389 (25%) and 888 (58%) kg ha −1 , respectively. The third irrigation at flowering produced no additional benefit. For comparable yields, the June sowing of the crop required 1–2 irrigations fewer than the July sowing. The results show that the crucial timing for a single irrigation was pod formation in the June-sown crop and pegging in the July-sown crop.

An analysis of the environmental limitation to yield of irrigated grain sorghum during the dry season in tropical Australia using a radiation, interception model

Variation in yield of irrigated grain sorghum (Sorghum bicolor L. Moench) grown during the dry season in tropical Australia was analysed in terms of the amount of photosynthetically active radiation (PAR) intercepted, its efficiency of use in dry matter production and the proportion of dry matter partitioned to grain. Three commercial hybrids (Texas 610SR, Dekalb DK55, Pacific Monsoon) grown under favourable conditions on two soil types (Cununurra Clay and Ord Sandy Loam) yielded similarly, but there was a significant effect of sowing date. Grain yield was highest (9.5 t ha-1 at 14% moisture) in the May sowing, with the lowest yield (7.4 t ha-1) being obtained in the April sowing. Yield was intermediate from a July sowing. Differences in grain yield across the dry season were not related to the amount of PAR intercepted, nor to the efficiency of conversion of intercepted PAR into net aboveground dry matter, but rather to differences in dry matter partitioning. A stable efficiency of conversion of 2.4 g MJ-1 of intercepted PAR was recorded for the entire crop cycle for sorghum crops growing under favourable growing conditions in this environment. This conversion efficiency for a tropical C4 cereal is similar to maximum values, but higher than average conversion efficiencies over the entire crop cycle obtained for temperate C3 cereals growing in temperate regions. Temperature did not affect this conversion efficiency, but had a pronounced effect on the duration of crop development.

Effect of sowing date on the growth and yield of kenaf (Hibiscus cannabinus) grown under irrigation in tropical Australia I. Phenology and seed production

Kenaf ( Hibiscus cannabinus ), a potential source of paper pulp, can be grown year-round with irrigation in tropical Australia. Seasonal changes in growth were studied by regular samplings from eleven monthly sowings of two contrasting cultivars grown in the Ord Irrigation Area in northern Western Australia. The two cultivars, Everglades 71 and Guatemala 4, behaved as facultative short-day plants, and there were differences between the cultivars in either the critical daylength required for floral initiation or in the duration of the period between initiation and flowering. Maximum seed yields and harvest indices were obtained in the January to July sowings of Everglades 71 and in the January to April sowings of Guatemala 4. Maximum yields did not differ significantly between cultivars. High yields were associated with increases in seed size and the number of capsules; the mean number of seeds per capsule was 12.8 and was independent of sowing date and cultivar. Seed yields were closely correlated with the duration of seed filling.

Genetic Evaluation and Path Analysis in Amaranthus

Estimates of genetic parameters, genotypic correlation coefficient and path analysis were made on seedling performance with 19 different genotype collections in Amaranthus sp. which is the chief source of green leafy vegetable in tropics. This study of seedling population for green leafy yield and its components was made during April and July seasons in 1976. The studies brought out significant differences among genotypes in respect of the yield components and also higher extent of variation as revealed by genetic estimates. The variation was high in length of stem and weight of plants followed by number of leaves, All these characters offered scope for selection in that order mentioned only, as inferred from estimates of H and GA. The genotypic correlation. was higher than phenotypic correlations in both the seasons. However, in respect of number of leaves per plant and weight of stem the relationship got reversed i.e. pheno- typic correlation was higher than genotypic in April as compared to July sowing. The direct effect of length of stem on yield as shown. by path analysis also was reversed in April season as compared to July season. The investigation also brought out the existance of strong Genotype x Environment (G x E) interactions in the diverse genetic population of Amaranthus.

Effects of Sowing Date on Forage and Seed Production of 14 Varieties of Cowpea (Vigna unguiculata)

SUMMARYFourteen varieties of cowpea (Vigna unguiculata (L.) Walp.) were compared for yields of forage and seed from two sowing dates, using various agronomic parameters. Yields ranged from 1048 to 5044, 185 to 920 and 864 to 3321 kg/ha for dry matter, crude protein and seed respectively, with advantages from spreading as against semi-erect types, and early rather than late July sowing. IVu 1283-1 and IVu 1283-2 effectively combined vegetative and seed yield, and appeared most suitable for fodder and seed production. A simple forage yield index (FYI), useful in yield prediction, was evolved.

トマトの1段密植栽培に関する研究

Our reseach on the single truss tomato culture was begun in an attempt to find out some means to increase the efficiency of tomato production. The results are summarized as follows1. Seeds of tomato cultivars FTVNR-3 and Dantobi-Yozu (self-topping variety) were sown nine times monthly on the 10th of each month from July 1974 to March 1975.The planting density was approximately 11, 000 plants per 10 a and the plants were all pinched at three leaves above the first inflorescence.2. Days from sowing to harvesting were about 170-188 in September, October, November and December sowings, about 140-155 in August, January and Feburuary sowings, and about 120 in March and July sowings respectively.Days after planting to harvesting were about 120 in September and October sowings, 85-100 in August, November and December sowings and about 65-75 in July, January, February and March sowings.3. The length and width of the uppermost leaf varied with sowing dates and these were affected principally by temperature. The stem length below the first inflorescence was determined by the temperature during propagation. Thus, it was much shorter in November, December and January sowings than in the other sowings.4. Total yields from each sowing over the year were in excess of 7 tons per 10 a, except for cultivar FTVNR-3 sown in October and cultivar Dantobi-Yozu sown in September.Percentage marketable fruits was, in both cultivars, as high as 85%, except for cultivar FTVNR-3 sown in October. Cultivar Dantobi-Yozu proved to be more suitable for single truss culture than cultivar FTVNR-3 since it produced stable yield throughout the year.5. The daily mean of solar radiation during the growth period and especially that during 30 days after anthesis were found to be highly correlated with the yield; the correlation coefficients being 0.758 (p<0.05) and 0.906 (p<0.001) to total yield and 0.774 (p<0.02) and 0.923 (p<0.001) to yield of marketable fruits, respectively.6. For a year-round cropping system of single truss tomatoes, however, seedlings should be planted at the stage just before the first anthesis to shorten the growing period of each crop, which is difficult to practice.Performance of three crops over the year is rather feasible by planting seedlings at five or six leaf stage and yet annual yield about 25 tons per 10 a can be obtained.7. Year-round culture of single truss tomatoes may increase the efficiency of tomato production and may bring profits to commercial growers, because 1) these plants give an annual yield higher than multi truss plants and their fruit quality is good, 2) the optimal environments are necessary to be kept only for the period of growth and development of the first inflorescence, which will simplify the cultivation and 3) the plants are supported by bar, thus the labour requirement for training is avoided.Furthermore, this cropping system makes it possible to make a planting programme over the year with flexibility from a viewpoint of the distribution of labor, and to regulate the production or shipping of tomato fruits taking aim at high price.

Preliminary experiments on the growth of kenaf (Hibiscus cannabinus) for paper pulp production in the Ord Irrigation Area, Western Australia

The results of agronomic studies with kenaf (Hibiscus cannabinus) grown for paper pulp production in the Ord Irrigation Area, Western Australia, are described. There were two experiments: one with cv. C2032 in which growth of the crop was studied at four seeding rates, two row spacings and four times of sowing, and a second in which the growth of cv. Guatemala -4 was followed at two times of sowing. It was demonstrated that year-round growth could be sustained with irrigation. A peak dry-matter yield of 25.6 tonnes ha-1 was achieved after 240 days from a July sowing of Guatemala -4. The yields of stem material from cv. C2032 increased as seeding rate was increased from 5 to 20 kg ha-1. Dry matter yields were higher with a narrow row spacing than with a wide row spacing; total dry matter production from crops sown on 1.5 m beds grown with 5 rows spaced 20 cm apart was 17 per cent higher than from single rows sown on 1 m ridges. The effect of row spacing was mainly in the yield of tops and foliage and there was no significant effect on stem yields. Data are given of the uptake of essential nutrients by kenaf crops. which illustrate the large quantities of nutrients removed by the crop. Ratooning of kenaf is shown to be possible provided it is cut at least 10 cm above ground level. The percentage of plants recovering after cutting increased as the height of cut was increased from 10 cm to 30 cm above ground level.

The influence of agronomic practices on the yield and oil content of safflower (Carthamus tinctorius) in the Wimmera region of Victoria

Between 1970 and 1972 three experiments were conducted in the Wimmera region of Victoria to investigate the effect of time of sowing, weed control, seeding rate and row spacing on the yield and oil content of safflower (Carthamus tinctorius). June sowing produced the best yields, although on occasions May or July sowings yielded equally well. There were large yield responses to weed control and seeding rates of at least 17 kg ha-1 were necessary. Higher yields were obtained from a row spacing of 0.18 m than from one of 0.36 m. Oil content was not affected by any experimental variable and showed little variation between the three years.