Browsing by Author "Doggett, H."
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Item Disruptive Selection in Crop Development(1968) Doggett, H.; Majisu, B.N.; East African Agricutlure and Forestry Research Organization. Serere. Soroti. UgandaCultivated sorghum was developed from a single wild species of the subsection Avundinacea by disruptive selection. It was maintained in the presence of the wild type under disruptive selection in spite of considerable gene flow between the two groups. An intermediate population consisting of early-generation hybrids and homozygous lines was established from the natural wild and cultivated populations. The presence of recently abandoned cultivations and field margins has enabled this intermediate population to become established and persist. The existence of the intermediate population ensures continued intro-gression between the wild and cultivated sorghums and enhances the variability of the cultivated crop whilst the wild type becomes modified in the direction of the cultivated forms. The development of maize can be explained along the same lines except that the crop is of greater antiquity and so divergence has continued further. The pattern Tripsacum-teosinte- maize of maize parallels the wild-intermediate-cultivated pattern of sorghum. The intermediate population could act as a bridge to transfer polyploidy from the wild type to the cultivated crop or polyploidy might arise within the intermediate population. This is shown in Sorghum almum and Zea perennis. [Cf. XXXV, 6435].Item Fertility Improvement in Auto tetraploid Sorghum. 3. Yields of Cultivated Tetraploids(1972) Majisu, B.N.; Doggett, H.; EAAFRO, Serere Research StationThe development of tetraploid grain sorghum as a crop plant continues to show promise. Yields from bulk populations and lines withdrawn from such populations are now approaching levels realized by good diploid varieties. It seems that tetraploid grain sorghum populations in which high levels of recombination are attained by the use of the genetic male-sterile ms3, should respond profitably to the application of recurrent selectionItem A History of the Work of the Mwabagole Rice Station, Lake Province, Tanzania(1965) Doggett, H.; East African Agricultural and Forest Research OrganizationThe Mwabagole Rice Station was started as a substation of the Western Research Centre, Ukiriguru, in 1935. It comprised some 20 acres of fertile mbuga soil, a heavy, black, deep-cracking, alkaline clay, containing nodules of limestone. (Milne 1938, Prentice 1943.) The station was situated eight miles from Ukiriguru on the shore of Mwanza Gulf at the mouth of a valley. The land sloped gently towards the Lake, and supplementary irrigation was provided by pumping from a furrow dug inland from the Lake, and allowing the water to flow back through the rice fields. Flood water coming down the valley after heavy rain could also be directed on to the landItem International aspects of Sorghum Research(1973) Doggett, H.; International Development Research Centre, Ottawa, CanadaThe contrast in productivity is very great between areas in which sorghums and millets have been rather recently introduced, mainly for stock feed, and traditional areas where these cereals are mainly used for human food. The 8.8 million hectares in America Yield from 16- 33 q I ha the 70 million hectares in Africa. Near East and Far East, yield 4.6 to 10.6 q/ha with a mean of 7.7 q/ha. That is a measure of the improvement than can be made in these crops, while the success of plant breeders in the United States in reshaping the crop into dwarf, day length insensitive. Highly productive hybrids has pointed the way to make these improvements. The example is already being followed in several countries, notably in India, where three hybrids have already been released.Item Mass Selection Systems for Sorghum,(1968) Doggett, H.Alternate generations of female choice and selfed plant mass selection may be applied to sorghum composites. Selection of steriles for agronomic characters and yield alternates with intense selection of fer tiles for yield. Gains are greater and seed set problems fewer. Composited collection entries using mSa contribute to the breeding populationsItem A Note on the Incidence of American Bollworm Heliothis Armigera (Hub.) (Noctuidae) in Sorghum(1964) Doggett, H.; East African Agriculture and Forestry Research Organization, SerereThe American bollworm, a troublesome pest of cotton in Africa, feeds on a wide range of plants. Maize is an important host, and often serves as a source of Heliothis adults which lay eggs on the cotton crop. At silking time, the moth may be attracted away from cotton to oviposit on the maize silks. The relative planting time of the maize determines whether it is harmful or beneficial to the cotton crop. Pearson (1958) has reviewed the literature on this. The sorghum crop in East Africa can also carry large American bollworm populations (Peat et al. 1955, Saville et al. 1958), and a high incidence of Heliothis larvae in types with compact panicles has been reported (Valentine 1954, Peat et al. 1955). The very similar New World bollworm H. zea (Boddie) is a sorghum pest in the U.S.A. (Quinby and Gaines 1942, Randolph 1959). The data reported here were collected at Ukiriguru, Tanganyika, in 1954-55.Item A Note on the Incidence of American Bollworm Heliothis Armigera (Hub.) (Noctuidae) In Sorghum(1964) Doggett, H.The American bollworm, a troublesome pest of cotton in Africa, feeds on a wide range of plants. Maize is an important host, and often serves as a source of Heliothis adults which lay eggs on the cotton crop. At silking time, the moth may be attracted away from cotton to oviposit on the maize silks. The relative planting time of the maize determines whether it is harmful or beneficial to the cotton crop. Pearson (1958) has reviewed the literature on this.Item Recurrent Selection in Sorghum(1968) Doggett, H.; Eberhart, S. A.Genetic male sterility is an important tool that permits the recurrent selection methods developed and used so successfully for maize to be applied to other crops. A breeding system utilizing recurrent selection has been initioated at Serere for sorghum (Sorghum bicolor L. Moench.) using Coes male sterility (msa). A detailed description of this breeding system is given including the compositing of the two breeding populations, the recurrent selection method used, and the subsequent development of hybrid varieties using the cytoplasmic male-sterility and restorers.Item Recurrent Selection in Sorghum Populations(1972) Doggett, H.TRADITIONAL methods of breeding improved varieties of mainly self pollinating crops have been very successful. Success has been greatest when characters controlled by relatively few genetic factors have been the main objects of selection. Height and length of maturity differences, some pest and disease resistances, and some leaf and panicle characters tend to belong to this category. Even in an out-pollinating crop such as maize, initial yield increase may be due largely to major characters, as in Harrison's Kenya hybrid H-611 (Eberhart et ai., 1967), where a short cob with many rows crossed to a long cob with few rows gave the plant breeder's dream of a long cob with many rows. Such major characters are seldom under simple major gene control.Item Recurrent Selection in Sorghum Populations(1972) Doggett, H.; E.A.A.F.R.O./U.S.A.I.D. Cereals Breeding Unit, Serere Research Station, Soroti, Uganda, and the Plant Breeding Institute, CambridgeSome elite varieties were crossed to the dwarf Goes male-sterile (ms3) and others were crossed to the ms3 segregates in the F2 generation. A total of 158 varieties was used. Populations were composited and then subjected to four systems of recurrent selection, (1) female choice mass selection, (2) alternating selfed plant and female choice mass selection, (3) alternating mass selection and (4) S1 testing. The S1 testing was most effective in yield improvement, resulting in an increase over the Serena control. Inbreeding depression in yield occurred on selfing, followed by a yield increase on recombination. Tall plants were favoured through plant competition and low yielding ms3 individuals were partially eliminated. All cultivated characters were maintained without difficulty.Item Sorghum(1963) Doggett, H.The article last month recalled the need for work on food crops because of rapid population increase, and indicated the important future for sorghum in the less well-watered areas of East Africa at medium and low altitudes. Work in East Africa on the sorghum crop has been in progress for some years. The Departments of Agriculture collected, introduced, and tested varieties, and did some selection and improvement work. Collections were made at Machakos in Kenya, Serere in Uganda, and Ukiriguru in Tanganyika.Item Sorghum(1963) Doggett, H.The value of sorghum to the East African economy will not be fully realised for a number of years, but it is undoubtedly going to make a big indirect contribution by reducing famine relief required in the marginal areas.Item Sorghum Breeding Research(1962) Doggett, H.; Jowett, D.The objectives of the sorghum work have been outlined in earlier reports. The studies of grain characters, and the inheritance studies of glume, awn and goose-neck have necessarily been in abeyance this year, as D. Jowett was in" the U.S.A. on a biometrics course for much of the time. Emphasis has been placed on the assessment of the potential value of diploid hybrid sorghum in East Africa, and the development of tetraploid cultivated hybrids in which the yield increment may be retained for several generations.Item The Sorghums and Sorghum Improvement in Tanganyika(1953) Doggett, H.The sorghums are grasses which have been cultivated for their grain since ancient times in Africa and Asia, and they probably originated in North Africa. They grow well on a wide range of soil types, and will thrive on a lower rainfall than maize, being much more drought resistant. At one time they were widely cultivated in Tanganyika, but have now been replaced in many parts by maize. This has had an unfortunate effect on food supplies in areas where the rainfall is uncertain or low, as sorghums yield much more consistently than maize under such conditions.Item Striga hermonthica on sorghum in East Africa(1965) Doggett, H.Striga hermonthica (Del.) Benth. (Scrophulariaceae) is a witchweed, hemiparisitic on sorghum, eleusine millet, maize, and various grasses in East Africa. It is indigenous to the area, occurring fairly frequently under wild conditions.Item Yield Increase from Sorghum Hybrids(1967) Doggett, H. ; East African Agriculture and Forestry Research Organization, EAAFRO/USAID/ARS Sorghum and Millets Research Unit, Serere Research Station, PO Soroti, UgandaIn variety trials at thirty sites or seasons in East Africa, the grain yield of the hybrid H × 58 when plotted against the yield of ‘Serena’, its pollinator parent, showed a linear regression with a coefficient value which did not differ from b=1.0 (ref. 1).Item Yields of maize, sorghum varieties sorghum hybrids in the East African Lowlands(1966) Jowett, D. ; Doggett, H.; E.A.A.F.R.O. Sorghum unit, source,1. Sorghum is capable of giving substantial yields under dry conditions where maize fails. 2. Sorghum can consistently out-yield maize in some areas under conditions of apparently adequate or excessive rainfall. 3. Low soil nutrient status, and/or poor soil water relations, interacting with the amount of rainfall were probably responsible for the low maize yields where precipitation in the growing season exceeded 15 in. 4. Some hybrids originating in the USA may be of immediate value in dry areas of East Africa. Such hybrids are generally …
