The American fruit culturist : containing directions for the propagation and culture of fruit trees in the nursery, orchid and garden : with descriptions of the principal American and foreign varieties cultivated in the United States /

Mode of access: Internet.

A natural history of new and rare ferns : containing species and varieties, none of which are included in any of the eight volumes of Ferns, British and exotic, amongst which are the new hymenophyllums and Trichomanes /

Includes index.

The potamogetons (pond weeds) of the British Isles, with descriptions of all the species, varieties and hybrids,

Issued in 15 parts, 1898-1915.

Minimising cold damage during reproductive development among temperate rice genotypes. I. Avoiding low temperature with the use of appropriate sowing time and photoperiod-sensitive varieties

Multiple-sown field trials in 4 consecutive years in the Riverina region of south-eastern Australia provided 24 different combinations of temperature and day length, which enabled the development of crop phenology models. A crop model was developed for 7 cultivars from diverse origins to identify if photoperiod sensitivity is involved in determining phenological development, and if that is advantageous in avoiding low-temperature damage. Cultivars that were mildly photoperiod-sensitive were identified from sowing to flowering and from panicle initiation to flowering. The crop models were run for 47 years of temperature data to quantify the risk of encountering low temperature during the critical young microspore stage for 5 different sowing dates. Cultivars that were mildly photoperiod-sensitive, such as Amaroo, had a reduced likelihood of encountering low temperature for a wider range of sowing dates compared with photoperiod-insensitive cultivars. The benefits of increased photoperiod sensitivity include greater sowing flexibility and reduced water use as growth duration is shortened when sowing is delayed. Determining the optimal sowing date also requires other considerations, e. g. the risk of cold damage at other sensitive stages such as flowering and the response of yield to a delay in flowering under non-limiting conditions. It was concluded that appropriate sowing time and the use of photoperiod-sensitive cultivars can be advantageous in the Riverina region in avoiding low temperature damage during reproductive development.

Contribution of potential yield, drought tolerance and escape to adaptation of 15 rice varieties in rainfed lowlands in Cambodia

In Cambodia, grain yield in rainfed lowland rice is often affected by drought during late vegetative or reproductive stage. Several experiments were conducted to quantify the contribution of potential yield, drought tolerance and drought escape mechanisms to yield under water stress conditions. In total nine pairs of well irrigated and simulated drought (by draining water) experiments were conducted. Potential yield was obtained under irrigation. Grain yields and flowering dates were recorded in 15 varieties. Drought tolerance was quantified by using drought response index (DRI), which is grain yield under drought adjusted for potential yield and flowering date of the variety. Drought escape is expressed as days to flower under drought conditions. Mean yield reduction due to drought of nine experiments was 27 % (range 12-44). The relative contribution of yield potential, flowering date and DRI to observe yield under drought were evaluated by multiple regression for each experiment. Potential yield accounted for 54% (with a range of 10-80) of the variation in actual yield under drought. This was followed by DRI and flowering date with 34 (with a range of 0-60) and 12 (with a range of 0-30) of the contribution, respectively. It is concluded that selecting for drought tolerance as well as for high yield potential would be important in developing cultivars for rainfed lowlands in Cambodia. Although flowering dates are important for drought escape, it had a small contribution probably because drought developed slowly in these experiments in Cambodia.

Molecular phylogenetics of the palm tribe Geonomeae, and differentiation of Geonoma macrostachys western Amazonian varieties

Phylogenetic analyses were performed on six genera and 46 species of the Neotropical palm tribe Geonomeae. The analyses were based on two low copy nuclear DNA sequences from the genes encoding phosphoribulokinase and RNA polymerase II. The basal node of the tribe was polytomous. Pholidostachys formed a monophyletic group. The currently accepted genera Calyptronoma and Calyptrogyne formed a well-supported clade with Calyptronoma resolved as paraphyletic to Calyptrogyne. Geonoma formed a strongly supported monophyletic group consisting of two main clades. ^ An evaluation of the genetic distinctness between Geonoma macrostachys varieties at a local and regional scale using inter-simple sequence repeat (ISSR) markers was performed. Clustering, ordination, and AMOVA suggested a lack of genetic distinctness between varieties at the regional level. A hierarchical AMOVA revealed that the genetic diversity mainly lies among the four localities sampled. A significant genetic differentiation between sympatric varieties occurred in one locality only. The current taxonomy of G. macrostachys, which recognizes only one species, was therefore supported. ^ The preferred habitat of sympatric G. macrostachys varieties with respect to edaphic, topographic, and light factors in three Peruvian lowland forests was studied. The two varieties were mostly encountered in different physiographically defined habitats, with variety acaulis occurring more often in floodplain forest and variety macrostachys in the tierra firme. Comparison of means tests revealed that nine to eleven of the 16 environmental variables were significantly different between varieties. Edaphic factors, mainly soil texture and K content, were better contributors than light conditions to distinguish the habitats occupied by the two varieties in all three study sites. It is concluded that habitat differentiation plays a role in the coexistence of these closely related species taxa. ^

Improving income and livelihood of poor farming household in Bangladesh through adoption of improved aquaculture technologies and varieties

Fish are an important part of Bangladeshi culture and diet. Bangladesh ranks among the top five freshwater fish producers in the world. Fish are abundant in the thousands of rivers, ponds, lakes and seasonal floodplains across the country. They are a major source of protein for people living near these water bodies. In Bangladesh, many households depend on fish farming for their livelihood. By growing fish in homestead ponds, households have a consistent supply of nutritious fish and can sell the surplus for an income. The USAID-funded Cereal Systems Initiative for South Asia in Bangladesh (CSISA-BD) aimed to increase the income of farming households through increased productivity of aquaculture systems. Key activities of the project included developing and disseminating appropriate improved agricultural technology and quality fish seeds to improve livelihoods, food security and nutrition.

Reconstruction of graded groupoids from graded Steinberg algebras

We show how to reconstruct a graded ample Hausdorff groupoid with topologically principal neutrally-graded component from the ring structure of its graded Steinberg algebra over any commutative integral domain with 1, together with the embedding of the canonical abelian subring of functions supported on the unit space. We deduce that diagonal-preserving ring isomorphism of Leavitt path algebras implies $C^*$-isomorphism of $C^*$-algebras for graphs $E$ and $F$ in which every cycle has an exit. This is a joint work with Joan Bosa, Roozbeh Hazrat and Aidan Sims.

Effect of ambient levels of ozone on photosynthetic components and radical scavenging system in leaves of African cowpea varieties

Tropospheric ozone (O3), a main component of photochemical oxidants, adversely affects not only human health but also vegetation. To clarify the long-term effects of ambient levels of tropospheric ozone (O3) on photosynthetic components and radical scavenging system in the leaves of cowpea ( Vigna unguiculata L.), two African varieties, Blackeye and Asontem, were grown in open-top chambers and exposed to filtered air (FA), non-filtered air (NF) or non-filtered air with additional O3 of approximately 50 nl l-1. Ambient levels of O3 significantly reduced chlorophyll concentration, quantum yield and activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), thus contributing to the reduction in net photosynthetic rate at the reproductive growth stage of both varieties; with no significant variety difference in the sensitivity to O3. The O3-induced significant reduction in catalase activity was observed in Blackeye at vegetative and reproductive growth stages; and in Asontem at reproductive growth stage. On the other hand, exposure to O3 significantly increased ascorbate peroxidase activity in Blackeye at reproductive stage and did not significantly affect that in Blackeye at vegetative growth stage and that in Asontem at both growth stages. At reproductive growth stage, activities of monodehydroascorbate reductase and glutathione reductase were significantly increased by the exposure to O3 in both varieties. The results obtained in this study suggest that, although ascorbate peroxidase, monodehydroascorbate reductase and glutathione reductase played important roles in scavenging O3-induced reactive oxygen species in the leaves, radical scavenging ability of these enzymes is not sufficient to avoid detrimental effects of ambient levels of O3 on photosynthesis in both African cowpea varieties.

GENETIC EVALUATION OF SEED TRAITS FROM INTRASPECIFIC CROSSING OF GENETICALLY DISTINCT WATERMELON VARIETIES

Citrullus lanatus (Thunb.) Matsumura and Nakai (Cucurbitaceae) is an important cucurbit crop worldwide. Global production of watermelon is about 90 million metric tonnes per annum, making it among the top five most consumed fresh fruits. The objective of this study was to evaluate seed variability in different segregating populations, and determine heritability of traits of watermelon. Interspecific crosses were made between two cultivars of C. lanatus (Bebu and Wlêwlê Small Seeds (WSS) were performed at Research Station of Nangui Abrogoua University in Abidjan, Côte d’Ivoire. There was wide variability between parental, F1, BC1 (first generation of back-crossing) and F2 seeds. Seeds of all hybrid populations were intermediate versus those of the parents. Also, crossing did not affect F1 and F2 seed characters, but affected those of BC1 because of maternal effects. Thus, back-crossing on Bebu cultivar produced seeds which looked like those of Bebu; while back-crossing on WSS cultivar produced seeds similar to those of WSS. Principal Component Analysis (PCA) and individuals repartitioning revealed that Bebu and WSS cultivars were genetically distinct and showed three main groups: two groups from each parental line and one from a recombinant line (hybrids). F2 population had a wide individual’s dispersion, and contained seeds of all other populations. High heritability was observed for all evaluated characters.

FIELD TOLERANCE OF SELECTED VARIETIES TO AND FUNGICIDE EFFICACY AGAINST ALTERNARIA BLIGHT OF SWEET POTATO

Alternaria blight (AB) of sweet potato ( Ipomoea batatas L. ), caused by Alternaria spp., was recently reported in South Africa, but is common in southern and eastern Africa. Elsewhere in the world, AB is controlled primarily using resistant varieties. Twenty-five sweet potato varieties/breeding lines, from different origins were assessed for tolerance to AB. The materials were planted in fields having a history of AB disease and rated for tolerance based on a General Disease Index (GDI), with the lowest scores representing tolerance, and the higher scores representing susceptibility. Variety 199062-1 had the lowest GDI value, and was the most tolerant to AB; while W119 had the highest GDI value and was the most susceptible to the disease. Other varieties/breeding lines showed a variation in GDI values between most tolerant and most susceptible. Among the fungicides tested under field conditions, the mixture azoxystrobin-difenoconazole was the most effective in reducing AB intensity. Fungicides pyraclostrobin-boscalid, unizeb, azoxystrobin-chlorothalonil and cymoxanil-mancozeb were also effective against the disease.