The response of germination and early seedling growth to levels of salinity (0, 50, 100, 150, 200 and 250 mM NaCl) were examined in single seed lots of ten modern rice genotypes. Unaged and deteriorated rice seeds were germinated in rolled paper towels and in Petri dishes. Initial seed quality, final germination, germination rate and early seedling growth were assessed. The samples of the rice genotypes differed in their initial seed quality (measured in terms of Ki). The effect of deterioration varied depending upon the initial seed quality and the severity of the treatment imposed. Ageing (using the technique of controlled deterioration, CD) for up to 24 h had no effect on final germination levels. Although CD for 30 h only reduced final germination slightly, ageing for 36 or 48 h reduced it greatly. Controlled deterioration for 36 h or longer reduced the final length and the rate of extension of both the plumule and radicle. Combining information about germination in salt solution with that about seed quality enabled a distinction to be made between varieties which performed poorly because they were genetically salt-susceptible from those which germinated poorly due to poor seed quality. It is argued that the seed vigour of seed lots used in genotype evaluation should be assessed in order to avoid discarding potentially useful genotypes because of poor physiological seed quality.

Improving grain yield and lodging resistance are two important targets for improving rice production. The aim of this study was to link grain yield and lodging resistance with growth patterns in rice. A nitrogen (N) fertilization experiment was conducted in 2020 and 2021, which consisted of two N rates (150 and 225 kg ha–1) and three N split-application ratios among the basal, early tillering, and panicle initiation stages (6:3:1, 5:3:2, and 4:3:3). The results demonstrated that increasing the N rate from 150 to 225 kg ha–1 did not affect grain yield but increased the plant lodging index by 16%. This increase in the plant lodging index was attributable to a higher plant fresh weight resulting from improved post-heading growth and a lower plant lodging load, which was partially due to a higher leaf area index. Altering the N split-application ratio from 6:3:1 to 4:3:3 increased grain yield by 4% but did not affect the plant lodging index in rice. The increase in grain yield was due to improved post-heading growth mainly resulting from increased radiation use efficiency during the post-heading period, which was partially attributable to increased specific leaf weight. An improvement in pre-heading growth in 2021 did not affect grain yield but increased the plant lodging load and decreased the plant lodging index by 36% compared to 2020. The improvement in pre-heading growth was due to a higher intercepted solar radiation resulting from higher leaf area index and incident solar radiation during the pre-heading period. The results of this study indicate that improving pre-heading growth can maintain grain yield and increase lodging resistance, while improving post-heading growth by increasing canopy radiation use efficiency (but not the leaf area index) can increase grain yield and maintain lodging resistance.

A field experiment was conducted to study the influence of 8- to 9-year-old nitrogen-fixing tree species (Faidherbia albida, Acacia ferruginea, Albizia lebbeck) and fertilizer nitrogen levels on yield and nitrogen uptake of intercropped cowpea (Vigna unguiculata). Grain and dry fodder yields of cowpea were reduced by 9% to 27% and by 11% to 35% respectively compared with the sole crop. Application of fertilizer nitrogen produced significantly higher yields. Nitrogen uptakes by leaves, stems and grain of cowpea were significantly reduced under A. ferruginea and A. lebbeck, but cowpea as sole crop and under F. albida showed no differences. Nitrogen uptake in different plant parts increased with increase in fertilizer nitrogen level.

Plant population studies were carried out in 1963 and 1964, including row spacing of 75 cm at different within-row densities, for purposes of comparison with the common practice of drilling at 15 cm spacing. Planting in spaced rows 75 cm apart, with increasing intra-row density from 55 to 175 seeds per metre of row, increased seed yield compared with drilling and a high intra-row density was better than low intra-row density for seed yield. The increase in seed yield was due to a higher number of stems, flowers and pods per unit area, and to a higher number of flowers forming mature pods. Seed set was better in spaced rows than at drill-spacing. Flowering took place over a shorter period, and the peak was attained earlier, at higher within-row density. Plant competition influenced plant branching as early as sixteen days after emergence. The relation between seedling development and seed yield is discussed.

The results are recorded of three field experiments, designed to investigate the effects of plant population and nitrogen fertilizer on growth and yield of maize. High yields of grain can be obtained in Trinidad provided plant populations are at least 20 000 plants per acre, nitrogenous fertilizer is added at the rate of 5–6 cwt per acre, weed and insect pests are controlled, and water is not a limiting factor at any stage of crop growth. Growth analysis has shown the importance of high leaf area indices in the production of high grain yields.

Indigenous crops, such as jute mallow (Corchorus olitorius L.) have high potential for improving nutrient efficiency and income source diversification of farmers in sub-Saharan Africa. A better understanding of plant responses to nitrogen (N) is essential in shedding light on the trend towards increasing fertilizer applications for commercially grown jute mallow. The aim of this study was to determine the critical N dilution curve in order to assess the N nutrition index (NNI) in jute mallow in southern Benin. Above-ground dry matter (DM) and N concentration were determined weekly during the 2010 and 2011 growing seasons and six N treatments of 0, 30, 60, 120, 180 or 240 kg N ha−1 were tested under irrigated conditions. A critical N curve (Nc = 3.35 W−0.18), where W is the DM in Mg per ha, was plotted based on the N concentration in the whole plant. The critical N concentration (Nc) represents the minimal N concentration required to achieve maximum growth. According to significant differences in DM at each sampling date, data points were divided into two groups representing either N deficient or N excess conditions. All data points in the N deficient group were under the critical N curve and most data points in the N excess group were on or above the critical N curve, therefore confirming the validity of the critical N curve determined in southern Benin. The NNI calculated as the ratio between the measured N concentration and predicted Nc, ranged from 0.55 to 1.30. The equation for the critical N curve and NNI determined in this study for jute mallow could potentially be used as a parameter for N application under non-deficient water conditions in southern Benin.

Fourteen out of 43 fungicides were selected, after laboratory screening, for field trials against coffee berry disease. Each fungicide was compared with a commercial cuprous oxide formulation and an unsprayed control, by assessing conidial production of bearing coffee branches and by recording the percentage of healthy ripe berries picked. In assessments of fungicidal efficiency, healthy ripe berry counts gave more consistent results than those obtained by measuring conidial production. The results from berry counts indicate that in these experiments Ortho Difolatan (BSI ‘Captafol’) was equal, but not significantly superior, to the standard formulation used in estate spraying. The annual rhythm of conidial production seems to have changed over the past five years. The significance of this is discussed in relation to the control of coffee berry disease.

Reduction of leaf area in sorghum without tillers (uniculm sorghum) might result in conservation of water at early stages of growth and hence in stability of grain yield under dry conditions. In two experiments in south-east Queensland, Australia, tillers were removed by hand to examine the growth of uniculm sorghum. Tiller removal promoted root development at the flag leaf stage but significantly reduced shoot dry matter and lowered grain yield by about 20% in a wet season. The saving in soil water as a result of tiller removal was relatively small but statistically significant.

Interactions between two contrasting photosynthetic photon flux densities (PPFD) and increasing Ca and P concentrations were analysed in N-fertilised (+N) and Rhizobium-inoculated (+Rh) Phaseolus vulgaris plants grown for 30 days in glasshouses. Plants were grown in sand-filled Leonard jars with 0.9 L N-free for +Rh plants or plus 6 mM KNO3 for +N plants nutrient solution, pH 6.2 in the lower compartment, and were subjected to midday PPFD ≥ 1650 ≤ 1800 mmol m−2 s−1/37±2°C air temperature (HI/HT) or PPDF ≥ 900 ≤ 1200 μmol m−2 s−1/26±2°C air temperature (MI/MT). The nutrient solutions were supplied with 1, 2, 3 or 4 mM P in combination with 1 or 4 mM Ca. Results revealed a 100% mortality of the HI/HT+Rh plants at the juvenile stage of growth. Whereas, all HI/HT+N plants reached the preflowering stage but showed smaller shoot masses, lower chlorophyll concentrations, unusually high chlorophyll a/b ratios and higher shoot nitrate concentrations when compared to values in +N plants grown at MI/MT. Increasing concentrations of P and Ca, or the daily spray of leaves with 2 mM propyl gallate (Pg), did not counteract the negative effects of HI/HT on +Rh and +N plants. Maximum growth, nodulation, chlorophyll concentration and catabolism of ureides in leaves were exclusively observed in +Rh plants grown under MI/MT conditions and supplied with 2 mM P and 1 mM Ca. In contrast, the greater growth of +N plants, associated with higher chlorophyll and nitrate concentrations, took place at MI/MT conditions combined with 1 mM P and 4 mM Ca. Pg further enhanced the growth of MI/MT+Rh and MI/MT+N plants grown at P < 2 mM, at 1 or 4 mM Ca, respectively. At MI/MT, there was a positive relationship between leaf carotenoid concentration and growth of +Rh and +N plants.

Evolutionary studies in the cottons began with the demonstration by Harland that true cottons could be divided into four genetically distinct species, each carrying an internally balanced genotype that was disrupted in crosses with any other. Harland's genetic classification has stood the test of time, and contributes substantially to our understanding of speciation in other genera, as for example, Phaseolus. In addition, it provides a genetic basis for the observations described by Anderson as ‘introgression’.

Studies of cottons found growing wild, and of their relationship to cultivars in the same areas, led to the hypothesis that all true cottons are cultivars, and those now found wild are escapes. This hypothesis, though it led to purposeful exploration of the distribution and relationships of the cottons, was found to be inadequate. A new approach to the relationships of the cottons became possible following Thoday's demonstration of ‘disruptive selection’ in Drosophila. The disruptive situation has been shown to obtain as between cultivars and their wild relatives in Sorghum and in a number of other crop plants.

Consideration of the time scale of agricultural evolution makes it clear that the recent origin theory is untenable, and a review of the status of the ‘wild’ cottons shows that they are adequately accounted for as weedy relatives of the cultivars, descended from common wild ancestors under disruptive selection.

It is concluded that crop plant evolution has gone on very largely within the balanced gene pools which Harland regarded as genetic species.

When wetted overnight by dew, dye spots on a cone-shaped paper ‘sensor’ will spread to an extent which depends on both the duration and the intensity of dewfall. Results from such a sensor have been compared with those from the de Wit recorder. Although only a qualitative assessment of surface wetness is obtained, the paper sensors are cheap and easily replicated, they can be stored for assessment later and they can be made in sizes to suit any particular situation in the field.

Broadsense heritability, and correlations of grain yield and related characters, were estimated in three crosses under two levels of soil fertility, which profoundly affected heritability of height and seed weight. Grain yield exhibited heritability of 51–81%, and in one cross significant heterosis in F2. Amongst yield-related characters only pods/plant and seeds/pod were both correlated to yield, and also lacked negative genotypic correlations with other economic characters. However, direct selection for grain yield was considered more efficient than indirect selection using yield-related characters.

The effects of frequency of potash fertilizer application and of different rates on sweet potato yields were studied in three different cropping systems on Njala upland soils. Fertilizers containing higher K rates (448 kg/ha sulphate of potash) and an N/K ratio of 3:4, gave maximum tuber and low vine yields with low vine/tuber ratios on intensively cropped areas, whereas fertilizers containing lower K rates (112 kg/ha sulphate of potash) and an N/K ratio of 3:1 gave maximum but relatively low tuber and relatively high vine yields, with relatively high vine/tuber ratios on newly cropped areas after seven years bush fallow. Two equal split applications of fertilizer is recommended under the weather conditions prevailing in this part of Sierra Leone.

On a large coconut plantation planted on a deep peat soil in Sumatra, Indonesia, hybrid coconut yields are stabilizing at values well below their potential, even in plots where known production factors have been mastered since the outset: land preparation, water control, and mineral fertilization. To explain this situation, five hypotheses have been proposed. They were tested one by one in field trials. The authors have demonstrated that the main reason for stabilized yields was the Lepidoptera root pest Sufetula spp. and conclude by considering lines of research for controlling this pest in the context of rehabilitation and replanting.

Results of an investigation to select intercrops showed that cotton can be grown with more profit with groundnut or gora paddy than when grown alone. Growing food or cash crops along with cotton enables an early crop to be produced and the practice may help to extend cotton cultivation in Chotanagpur and Santhal Parganas, a potential cotton belt of the future.

This study, designed to investigate trade-offs between forage yields, feed quality and labour use in fitting a newly introduced crop, Lablab purpureus, into an existing farming system, adopted distinct applied and adaptive research approaches. The applied research component compared forage yields, nutrient contents and feeding qualities of L. purpureus harvested at 100, 114, 128 or 142 d after planting in an on-farm trial. The adaptive research investigated how farmers incorporated L. purpureus cultivaton into their farming calendars given the constraints of labour for planting and harvesting.

Harvested dry matter yields from the on-farm experiment were 1.28, 1.98, 1.74 and 1.44 t ha−1. The resultant hays were fed to four groups each of five Bunaji lactating cows in an on-farm feeding trial over a 10-week period. Ranking the various harvests for yield, the hays for feed value, animal responses to the feed consumed and the quality of animal products on a linear scale (1 to 4) to estimate a composite utility index, showed that harvesting at 114 d after planting gave the most desirable overall benefits.

The survey for adaptive research showed bimodal rainfed and irrigated cultivation patterns for L. purpureus. Peaks were observed in September (31% of farmers) and November (24%) for planting, and in December (39.4%) and March (15%) for harvesting. Forage yields were, however, highest for the 3% of farmers who afforded labour to plant in July and harvest in October. The lack of congruence between highest forage yield periods and the peaks of cultivation of L. purpureus by farmers in the study area was mostly explained by very significant differences in the cost of hired and household labour in different months. Thus, socio-economic and cultural factors, including stakeholders' participation, need to be considered along with applied research results when recommending forage species for farmers' adoption.

Suggested rules are given for the presentation of numerical data in a scientific agricultural journal. These are that all tables of numerical results should be sufficiently clear to render unnecessary any reference to the accompanying text; and that treatment means (and other statistics) should always be accompanied by their standard errors, rather than by least significant differences or by asterisks showing the results of significance texts. Examples are given of correct and incorrect presentation of results, and the graphical presentation of results is also discussed.

Problems of potato culture are discussed with respect to photosensitivity, seed stock degeneration, and the maturity behaviour of varieties bred in the temperate world. Varieties adapted to temperate climates, when grown under sub-tropical conditions, matured earlier and yielded less than when grown under temperate conditions. The complex problems involved in combining several desirable attributes in a variety are discussed in the light of current breeding procedures and new approaches to solve several of the problems are indicated. Data on the bionomics of aphid vectors of potato viruses suggest methods for maintaining high health standards in breeders' stocks. Techniques are discussed for raising large populations of seedlings from true seeds under sub-tropical conditions.