BACKGROUND The fall armyworm (FAW) Spodoptera frugiperda (J. E. Smith), native to the Americas, is a new invasive pest that was reported in India for the first time in May 2018. Being polyphagous, FAW can infest several different hosts and increase its population all year round. In this context, the present study was conducted under laboratory conditions to evaluate the biological parameters of FAW on four different hosts, Zea mays (maize), Gossypium hirsutum (cotton), Ricinus communis (castor) and Brassica oleracea var. botrytis (cauliflower), and a semi‐synthetic diet. RESULTS The shortest life cycle of 32.8 ± 0.52 days in males and 34.1 ± 0.43 days in females was observed on maize. Semi‐synthetic diet was superior in terms of higher mean fecundity (1324.6 ± 61.21 eggs), larval weight (503 ± 0.02 mg), pupal weight (263 ± 0.01 mg) and adult female weight (128 ± 0.0 mg) compared with natural hosts. Cotton was the least preferred host with a longer life cycle of 49.5 ± 0.50 days. Head capsule width and length were measured and the growth rate was validated using Dyar's rule. The mean width and length of the head capsule of first‐instar larvae of FAW on different hosts was 0.35 ± 0.00 mm. The maximum width (2.76 ± 0.03 mm) and length (2.31 ± 0.03 mm) were observed in sixth‐instar larvae grown on diet. CONCLUSION The results of this study will be instrumental in understanding and formulating management strategies for FAW.
Results of cytogenetic studies of 2 amphidiploids, 0. glaberrima -sativa and 0. sativa -breviligulata, are reported for the first time in the genus Oryza. All the 3 species have 2n = 24 chromosomes. They were produced by treating buds of F1 stubbles with 0.1% colchicine solution.The 'gigas' effect of polyploidy was observed in both the amphidiploids. While the F1 hybrids were completely sterile polyploidy resulted in 75.0% pollen fertility in both, with 47.0% spikelet fertility in 0. glaberrima -sativa and 12.7% in 0. sativabreviligulata, Meiosis in the 2 amphidiploids was generally similar. Quadrivalents ranging from 0 to 12 were observed with 2 modes at 61V and 81V. The average number of IVs in the Cs and Cs generations ranged from 6.2 to 7.8. Segregation of characters was observed in the Cs and Cs generations in 0. glaberrima -sativa. The Cs plants segregated for spikelet size and hairiness. Of the 4 Ca progenies studied, one segregated in the ratio 3:l for the presence of anthocyanin pigmentation and hairiness of spikelets.The occurrence of IVs in high frequency and the segregation for differences in characters of the original parents noted in 0. glaberrima -sativa are similar to the results reported from autotetraploids of 0. sativa. It is suggested that these results point out to the rather close structural similarity in the chromosome complements of the 3 species and provide experimental evidence to the theory that the 2 cultivated species 0. sativa and 0. glaberrima have evolved independently from a common species 0. perennis. Ever since the property of colchicine to induce ploidy in plants was discovered in 1937, it has been used with considerable advantage in cytogenetical research, primarily in obtaining information on the nature of origin of species and species differences. Such studies have been made extensively with synthetic polyploids -both autopolyploids and amphidiploids -in such genera as Triticum, Brassica, Gossypium and Nicotiana. In the genus Oryza, though autopolyploids, both naturally occurring and induced, and polyploids of interracial hybrids of 0. sativa (subsp. indica and sub sp.japonica) have been studied by a number of workers, no amphidiploids have so far been reported. The present paper deals with the cytogenetical studies made on 2 amphidiploids, 0. glaberrima STEUD. x 0. sativa LINN. and 0. sativa LINN. x 0. breviliguZata A. CHEVAL. et ROEHRICH, during 1958-1959 All the 3 species are diploids (2n = 24).
We present Bhās .ā citra, 1 a dialect mapping system for South Asia built on a database of linguistic studies of languages of the region annotated for topic and location data. We analyse language coverage and look towards applications to typology by visualising example datasets. The application is not only meant to be useful for feature mapping, but also serves as a new kind of interactive bibliography for linguists of South Asian languages.
The paper reports the results of genetic studies made in four interspecific hybrids of the genus Oryza, and the data are employed to discuss the inter-relationships between the different species . The characters of wild parents were found to be dominant in the Fl hybrids .In O. sativa (variety Fukoku) x O . perennis subsp. balunga, the inheritance of the eight characters studied was found to be of the same nature as that of complementary, modifying, duplicating and polygenic types involving two or three genes . In O . perennis (Cuban type) x O . perennis subsp. balunga, the interesting feature was the occurrence of recessive characters (typical of cultivated rices) in the F2 population, even though the two parents carried the dominant wild characters . This should be possible only by the operation of duplicate genes and such a mode of inheritance was observed for three characters . No definite Mendelian ratios could be got for the remaining five characters studied . The appearance of characters of cultivated rices has been suggested to point to the ability of O . perennis to give rise to O . sativa through natural crossing and selection . In O . glaberrima x O . perennis subsp. balunga, the ten characters studied segregated in monogenic or digenic fashion . When digenic, these characters exhibited complementary or inhibitory factor interactions . In O . glaberrima x O . breviligulata, the simple mode of inheritance in the F2 generation has been suggested to indicate the close relationship of the two species .Some of the general features of the hybrids and segregating populations studied were the vigorous and fertile F is followed by the appearance of weak and unthrifty plants in the F2 generation and the tendency for the parental characters to inherit together . The appearance of plants looking similar to O . sativa var . fatua in the F2 populations of O . sativa x O . perennis, and of O . stapfii in the F2s of O . glaberrima x O . perennis has been supposed to provide further evidence on the hybrid origin of these two forms .
Studies were carried out at the Rice Research Station, Pattambi (Kerala) to ascertain the extent of damage caused by the rice gall midge Pachydiplosis oryzae (Wood-Mason) to IR. 8-paddy crop planted at different fortnightly intervals during 1987-6g to 1971-72. The Influence of rainfall, relative humidity, minimum and maximum temperatures on infestation by the pest was also investigated. The pest incidence was found to be maximum and sharp decline for crops planted in June and first fortnight of July respectively, on the basis of the occurrence of silver shoots at 45 days after planting. The percentage incidence of silver shoots caused by the pest is correlated positively with rainfall and negatively with maximum temperature. Partial correlation studies have revealed the Independent Influence of rainfall and maximum temperature on gall midge infestation.
Soviet intervention i!i Afghanistan clearly iridicates the strategic iiiplicatioris of its localion. Tlie political instability iii the regiori (rise of funilanieii talisiir iii Iran, Irari-Iraq War aiid so on) has added to this significaiice. Be that as it may, Afghaliistati's situation can be expressed ili ternis of its susceptibility to external presstires mil irirense facrioiinlis~~i wilhiii rke lanil-locked state's dyrramic popirlations. This latter aspect had divided the coirrrtry several times over. Afghan foreigri policy, therdore, has been viewed in this perspective. The present article reviews the stated facts to highlight the geographical sigii~cance of the lacatioii and its impact on the foreign policy.hitrodicetion of the arnred forces iii iiatiorial politics (this formed an iiiiportartt eleineiit iri the couii fry's politics right frorii rhe beginning) has beeri the most cotispicuoiis developnie~it; it detcr~iiirreil the nho's and what's of the goverriiiient. Traditional pressure groups, despite ref airiirig sonie of their old hold 011 the society, had given way to radical groups or fac t ions, armed forces and insurgent elemen ts. These perie tra t etl varioirs strata of the Afghari society. Since 1963, when political liberalisation arid participa t ion was in t rodirced, clisrrcptive terideiicies gradirnlly iiiipiriged 011 the state's activities. Generally, this was eviileiit between 1963-13 and was particirlarly so after the 1973 coup, wheri the Monarchy was replaced by a re~iublicari reginie iriider Dair. Both, the Armed Forces arid the COINniunist Party were irivolved but were sidelined once power was secured. This change did not bririg the expected transfoniiations iii the patterns of administration. The change was orily in naiiie and power was still coricentrated with Daud who begmi to implement his own policies that emerged between 1953-63. The period of his first stint iri power coincided wiih an aggravation of problems, political and econoniic, caused by a closure of transit facilities. However, this pause was jitlly exploited by the radical parties who graditally brought the ifomitiatit eleiiietits of the Armed Forces under their infliieiice, so that, they were nble to deliver a coup d'etat under the leadership of Tarakki iii April 1978. Tlie iiew reginie was iiot able to maintain eflective control over the political situation that for' the next twenty nioiitlis brought iiiteriral political itistabiliry to its height and
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.