http://ir.lib.ruh.ac.lk/handle/iruor/7538 2026-04-26T18:26:37Z 2026-04-26T18:26:37Z Han, H.W. Jiang, C.J. Xu, C.Y. Sun, H.J. Yuan, G.D. Yu, J. Wang, C.T. http://ir.lib.ruh.ac.lk/handle/iruor/19792 2025-07-15T04:46:42Z 2025-03-31T00:00:00Z

Leaf stomatal characteristics and key agronomic traits of intersectional peanut f1 hybrids between huayu 665 and arachis paraguariensis Han, H.W.; Jiang, C.J.; Xu, C.Y.; Sun, H.J.; Yuan, G.D.; Yu, J.; Wang, C.T. The cultivated peanut is a globally important crop, valued for its oil, food, and feed uses, but has a narrow genetic base. High stress resistance, good-quality and high-yield factors residing in wild species constitute valuable resources for genetic improvement of the peanut cultigen. Some wild species are used as groundcovers, while others utilized as potted plants. Previous studies have focused on compatible wild relatives, but there is a lack of research on the use of incompatible Arachis species. This study aimed to investigate the hybrids produced from a cross between the peanut cultivar Huayu 665 and the incompatible species Arachis paraguariensis, enhancing our understanding of distant hybridization. Ture F1 intersectional hybrids were identified by transposon element marker pairs. Leaf stomata were observed, and main agronomic traits were investigated. The F1 hybrids exhibited significantly fewer large stomata (14.78 per mm²) and longer stomata (26.52 μm) on the abaxial leaf epidermis compared to the female parent, Huayu 665, which had 20.56 per mm² and 16.86 μm, respectively. Compared to Huayu 665, the F1 hybrids exhibited a longer first pair of lateral branches, a wider range of seed set, and more branches, but produced fewer pods per plant. A hybrid with a plant type similar to the female parent was identified. The authenticity of the hybrids was confirmed through molecular, anatomical, and morphological analyses. The hybrid resembling the cultigen may accelerate the utilization of incompatible wild species in peanut breeding. However, its chromosome composition is yet to be determined. To avoid missing true hybrid identification in peanut remote crosses, use of molecular markers distributed across different chromosomes of the wild species was proposed.

2025-03-31T00:00:00Z Senanayake, N. http://ir.lib.ruh.ac.lk/handle/iruor/8745 2024-11-05T09:57:25Z 2022-01-01T00:00:00Z

RICE PRODUCTION UNDER THE ORGANIC FERTILIZER USE POLICY IN SRI LANKA Senanayake, N. Rice cultivation in the country dates back to time immemorial, though the rice production was not sufficient to meet the demand with the increasing population lately. Rice breeding work started during the last phase of the colonial era and continued with the green revolution in the 1960s. As a result, the national average yield improved from 0.75mt/ha during the colonial time to 4.82 mt/ha today. Improved varieties today are highly responsive to inorganic fertilizers, high tillering and high yielding with some insect and disease resistance. However, inorganic fertilizer use in the country since the 1950s resulted in soil degradation and was further aggravated by inappropriate mechanization and weedicide use. This led the department of agriculture to recommend the use of organic matter to supplement inorganic fertilizer applications to sustain production. The situation was viewed superficially and the government took a policy decision to ban the import of inorganic fertilizer and agrochemicals without any valid research data or suitable organic alternatives for pesticides, disregarding the high shriek from the eminent scientists and paddy farmers. Ad-hoc fertilizer recommendations provided to farmers and the use of alien fertilizer formulations without any field research data locally were either rejected or used sparingly by the farming community. This huge cry was later politicized and prevented the President to change his decision, though some flexibility was approved. Policy decisions ultimately ended up in huge rice imports, amidst a shortage of foreign currency, to prevent food shortages. Organic fertilizer sources are many though their availability individually is not adequate for the rice sector. There are many compost producers whose products vary in nutritive content from producer to producer and from batch to batch of the same producer. Thus, organic fertilizer standardization and providing a single fertilizer recommendation is impossible if not time and labor intensive and financially very expensive. However, a concrete single recommendation for organic fertilizer is not possible even with extensive field experimentation. Therefore use of organic fertilizer as a basal application alone with inorganic fertilizer to meet the peak nutrient demand at several stages of rice plant growth can be a good option to sustain rice production, of course after a minimum of two season’s adaptive field research. This paper reviews the pros and cons of sustainable rice production in the country under the organic fertilizer policy of the government.

2022-01-01T00:00:00Z Kasige, R.H. Dangalle, C.D. Pallewatta, N. Perera, M.T.M.D.R. http://ir.lib.ruh.ac.lk/handle/iruor/8744 2024-10-15T10:25:07Z 2022-01-01T00:00:00Z

LABORATORY STUDIES OF LARVAL CANNIBALISM IN SAME-AGE CONSPECIFICS OF FALL ARMYWORM, Spodoptera frugiperda (J.E. SMITH) (LEPIDOPTERA, NOCTUIDEA) IN MAIZE Kasige, R.H.; Dangalle, C.D.; Pallewatta, N.; Perera, M.T.M.D.R. Fall Armyworm (Spodoptera frugiperda) (FAW) is an economically important pest worldwide and larval cannibalism is documented as one of its significant behaviors under field and laboratory conditions. The incidence of larval cannibalism amongst same-age larvae of Fall Armyworm was investigated under laboratory conditions using 73 laboratory trials with not less than five trials for each instar stage. Each instar stage was provided with their conspecifics along with sufficient food. Direct observations were carried out in 24 hour time laps to record the missing larvae which were presumed as cannibalized. The mean cannibalism proportion was calculated for each larval stage. All larval stages except the first and second instar stages displayed same-age conspecific cannibalism. An increasing trend of the mean cannibalism proportion was observed from the third (0.16±0.04) to the fifth instar stage (0.22±0.05) with the highest value recorded for the fifth larval instars. The trend dropped at the sixth instar stage. The study suggests that larval cannibalism is evident amongst same-age larval instars of Spodoptera frugiperda, which may affect ecological relationships between organisms of a system.

2022-01-01T00:00:00Z Yesmin, M.A. Salim, M. Monshi, F.I. Hasan, A.K. Hannan, A. Islam, S.S. Tabassum, R. http://ir.lib.ruh.ac.lk/handle/iruor/8743 2024-10-22T07:57:04Z 2022-01-01T00:00:00Z

MORPHO-PHYSIOLOGICAL AND GENETIC CHARACTERIZATION OF TRANSPLANTED AMAN RICE VARIETIES UNDER OLD BRAHMAPUTRA FLOOD PLAIN (AEZ-9) IN BANGLADESH Yesmin, M.A.; Salim, M.; Monshi, F.I.; Hasan, A.K.; Hannan, A.; Islam, S.S.; Tabassum, R. Rice is a staple food in terms of acreage and production in Bangladesh. The assessment of genetic variability in rice genotypes is essential to identify suitable characters for its further improvement. An experiment was carried out to study the morpho-physiological and genetic characteristics of transplanted Aman (one of the important rice growing seasons in Bangladesh) rice cultivars. Ten Aman rice varieties were tested as treatments and the experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. The analysis of morpho-physiological traits in tested rice varieties demonstrated that the higher number of effective tillers per hill, panicle length, grains per panicle and 1000 grain weight was the most yield contributing traits those were influenced to produce higher grain yield. In terms of genetic traits analyses, all the studied traits exhibited high heritability (>60%) except panicle length. And in correlation studies, grain yield showed the significant positive correlation with 1000 seed weight, panicle length, effective tiller number per hill along with biological yield, straw yield and harvest index. Moreover, path coefficient analysis revealed that biological yield and harvest index showed a high and positive direct effect on grain yield. Thus, after studying different traits among ten varieties of Aman rice there after considering the three categories, hybrid varieties performed better followed by HYV compared to traditional rice varieties. And the Dhanigold variety might be recommended as a higher yield producing cultivar along with the economic return.

2022-01-01T00:00:00Z