Host-plant resistance in the management of Sorghum stem borers

Of the 23 stem borers infesting sorghum, Chilo partellus, Busseola fusca, sesamia cretica, s. calamistis, Eldna saccharina spp. are the important species occuring in various sorghum areas of the world. Host-Plant resistance offers an economic, effective and long term solution to manage these'internal feeders' either alone or in conjuction with culture, biological and chemical methods of control. The development of host-plant resistance to crop plants requires. (1) the detailed knowledge on the bio-ecology of the pest and its relationship with host plant, (2) development of an effective and reliable screening techniques (s), (3) reliable criteria for measuring resistance, (4) identification of strong and stable source(s) of resistance, and (5) incorporation of gene(s) for resistance into the elite background. This paper deals with all the outlined apects related to stem borers in general and Chilo partellus in particular and also discusses the scope of host-plant resistance in the integrated management of stem borers in sorghu

Mechanisms of Stem Borer Resistance in Sorghum

A number of sorghum genotypes resistant to the spotted stem borer (Chilo partellus Swinhoe) have been identified using natural and artificial infestations at ICRISAT. Resistance is attributed to ovipositional nonpreference and antibiosis mechanisms. The major plant characters identified include early panicle initiation and rapid internode elongation. In resistant genotypes, these factors were reflected in the success of first instar larval establishment in the leaf whorl, interval between hatching and larvae boring in the stem, larval mass, and survival rate. Success of the first instar larvae to establish in the whorl is also influenced by physical and chemical plant characteristics. A chemical factor in the surface wax of some sorghum genotypes is associated with larval disorientation

Breeding for Resistance to Stem Borer ( Chilo partellus Swinhoe) in Sorghum

Stem borer (Chilo partellus Swinhoe) is the most important pest of sorghum. Progress has been made in developing borer-resistant breeding lines with moderate yield and acceptable grain quality. Sorghum variety, ICSV 700, has high levels of stem borer resistance across several seasons and locations. Borer resistance is a quantitatively inherited trait governed by additive and nonadditive genes. Epistatic gene effects are more pronounced under artificial borer infestation. Cytoplasmic effects appear to be present

Bollworm incidence as affected by sowing date, nitrogen application and plant populanon in upland cotton

Trials were conducted to know the effect of sowing date, nitrogen application and plant population levels on the incidence of bollworms (pink and spotted bollworms) at Cotton Research Station, Sirsa (Haryana) during the crop seasons 1979–80 and 1980–81. Incidence of pink boll-worm on flowers and spotted bollworm on bolls was more in early sown crop than the normal and late sown crop. Late sown crop recorded highest level of pink bollworm incidence on bolls and number of diapausing larvae. Application of nitrogen resulted in higher incidence of bollworms whereas plant population levels did not influence the bollworm incidenc

Raising awareness of the accessibility challenges in mathematics MOOCs

MOOCs provide learning environments that make it easier for learners to study from anywhere, at their own pace and with open access to content. This has revolutionised the field of eLearning, but accessibility continues to be a problem, even more so if we include the complexity of the STEM disciplines which have their own specific characteristics. This work presents an analysis of the accessibility of several MOOC platforms which provide courses in mathematics. We attempt to visualise the main web accessibility problems and challenges that disabled learners could face in taking these types of courses, both in general and specifically in the context of the subject of mathematics

Poly(A) RNA codistribution with microfilaments: evaluation by in situ hybridization and quantitative digital imaging microscopy

The distribution of poly(A) RNA has been visualized in single cells using high-resolution fluorescent in situ hybridization. Digital imaging microscopy was used to quantitate the signal in various cellular compartments. Most of the poly(A) signal remained associated with the cellular filament systems after solubilization of membranes with Triton, dissociation of ribosomes with puromycin, and digestion of non-poly(A) RNA with ribonuclease A and T1. The actin filaments were shown to be the predominant cellular structural elements associating with the poly(A) because low doses of cytochalasin released about two-thirds of the poly(A). An approach to assess the extent of colocalization of two images was devised using in situ hybridization to poly(A) in combination with probes for ribosomes, membranes, or F-actin. Digital imaging microscopy showed that most poly(A) spatially distributes most significantly with ribosomes, slightly less with F-actin, and least of all with membranes. The results suggest a mechanism for anchoring (and perhaps moving) much of the cellular mRNA utilizing the interaction between actin filaments and poly(A)

Mass Rearing Of Chilo Spp. On Artificial Diets And Its Use In Resistance Screening

Several species of Chilo are serious pests of cereal crops. The important species attacking cereals are Chilo agamemnon, C. orichalcociliellus and C. parrrllus on malze and sorghum; C. auricilius and C. zacconius on sugar-cane, and rice; C. suppressalis on rice; and C. sacchariphagus indicus on sugar-cane. Insects are reared In the laboratory on natural and artificial diets for various purposes, namely for insecticide testing, hormone and pheromone manipulation, biological control, host-plant resistance, etc. Rearing of an insect In the laboratory requires rearing facilities, colony establishment, research and development of rearing techhiques, resources, and maintenance of insect quality. All these aspects for rearing major Chilo spp. have been discussed. However, detailed information is available only for C. partellusand C.supprersalis. Techniques used for resistance screening anddamageevaluation against spotted stem borer, C. partellus using naturally occurring populatlon and artificial infestation are described