After the Green Revolution, the increase in the choice of modern varieties at the expense of landraces has become a major cause of varietal loss. The preference, choice, and the economy of rice (Oryza sativa L.) largely depend on its physicochemical and cooking properties, which are found to be superior for landraces than modern varieties. In this study, we assessed and evaluated milled rice of 30 rice landraces on their physicochemical and cooking characteristics which aim to promote the revival of old landraces. Six parameters of physical properties, four parameters of chemical properties, and five parameters of cooking properties were evaluated based on the standard protocols. Significant variations (p<0.05) were found in all the properties that were evaluated. The result showed that the highest milling recovery was found in Indrabeli (75.55%) whereas the lowest was found in Kalo Masino (66.98%) and bulk density ranged from 0.81 g/cm3 to 0.88 g/cm3 showing not much variability. Although most of them were of medium grain type, their 1000 kernel weight varied between 12.62 g and 25.65 g. From the observed chemical properties, Pahelo Anadi (9.73±0.55 mm) showed the highest gel consistency and lowest apparent amylose content (7.23±0.36%). Also, 13% of landraces possessed strong aroma while noble cooking properties were showed by Thakali Lahare Marsi with the highest elongation ratio (2.41±0.05) and by Chiniya with the lowest gruel solid loss (0.033±0.03%) and minimum optimum cooking time (23.45±0.03 min). In the principal component analysis, the first four principal components retained 73.8% of the variance. The first and second principal components were mostly related with the physical and chemical characteristics while the third and fourth principal components were concerned with cooking characters. Superior characters possessed by rice landraces can be further assessed for the breeding programs so that the cultivation of these cherished rice landraces can be enhanced.

The magnitude and nature of genetic divergence play a vital role in the selection of the desirable landraces for its utilization in the breeding program. A study was carried out with 30 rice landraces at the Institute of Agriculture and Animal Science, Lamjung Campus, during June–November 2018 to determine relation among individuals, estimate the relative contribution of various traits of rice using principal component analysis, and identify the potential parents for hybridization using Mahalanobis distance (D2). The principal component analysis revealed that five among the thirteen principal components were significant (eigenvalue >1) and contributed to 29.96%, 20.26%, 13.56%, 11.68%, and 9.22% of the total variance, respectively. PC1 included the traits that were related mostly to the yield, yield attributing, and grain characteristics. Landraces from Anadi group, Jetho Budo, Jarneli, and Rato Masino performed well in PC1 while landraces such as Mansara, Pakhe Sali, and Aanga performed well in PC2. The landraces were grouped into six clusters where 12 landraces were grouped into cluster I. Cluster analysis showed maximum and minimum intracluster distance in cluster VI (D2 = 35.77) and cluster I (D2 = 18.59), respectively. The maximum intercluster distance was obtained between clusters V and VI (D2 = 40.18) followed by clusters III and VI (D2 = 36.17) and clusters IV and VI (D2 = 35.74). Cluster III showed the highest mean value for grain width, flag leaf breadth, yield, and minimum mean value for plant height while mean values of total grain per panicle, filled grain percentage, and thousand-grain weight were maximum in cluster IV. Mean values of effective tiller and kernel width were found maximum in clusters V and VI, respectively. Landraces from clusters V and VI or clusters III and VI or clusters IV and VI can be used in the hybridization program to develop the superior hybrids by exploiting heterosis in segregating generation.

Nitrogen (N) deficiency limits net carbon assimilation rates (AN), but the relative N sensitivities of photosynthetic component processes and carbon loss mechanisms remain relatively unexplored for field-grown cotton. Therefore, the objective of the current study was to define the relative sensitivity of individual physiological processes driving N deficiency-induced declines in AN for field-grown cotton. Among the potential diffusional limitations evaluated, mesophyll conductance was the only parameter substantially reduced by N deficiency, but this did not affect CO2 availability in the chloroplast. A number of metabolic processes were negatively impacted by N deficiency and these effects were more pronounced at lower leaf positions in the cotton canopy. RuBP regeneration and carboxylation, AN, and gross photosynthesis were the most sensitive metabolic processes to N deficiency, whereas photosynthetic electron transport processes, electron flux to photorespiration, and dark respiration exhibited intermediate sensitivity to N deficiency. Among thylakoid specific processes, the quantum yield of PSI end electron acceptor reduction was the most sensitive process to N deficiency. It was concluded that AN is primarily limited by Rubisco carboxylation and RuBP regeneration under N deficiency in field grown cotton and the differential N-sensitivities of the photosynthetic process and carbon loss mechanisms contributed significantly to photosynthetic declines.

The variability in the rice landraces is the source of variation and offers substantial opportunity for the development of new varieties through the selection. Exploring diversity and variability of landraces is utmost for rice improvement. The objective of the study was to assess diversity indices, magnitude of genetic variability, heritability, genetic advance for the yield, and yield contributing traits. An experiment was carried out in alpha-lattice with 30 landraces, two replications in the Agronomy farm of IAAS, Lamjung Campus, during June-November, 2018. Shannon and Simpson's indices were calculated for 18 qualitative traits. The value of the Shannon and Simpson index ranged 0.15-1.41 and 0.07- 0.75, respectively. Landraces showed significant variations (p<0.001) for all 13 qualitative traits studied. The higher value of the phenotypic coefficient of variation (PCV) compared to the corresponding genotypic coefficient of variation (GCV) for all the studied traits indicated the influence of the environment. The filled-grain per panicle exhibited a high estimate of PCV and GCV, followed by the effective tiller and filled grain percentage. High heritability, along with high genetic advance was found in 10 traits, including 1000 grain weight, grain length, and filled grain per panicle indicated the presence of additive gene action. Direct selection of characters of these traits based on phenotypic expression by a selection method will be more reliable for yield improvement. The study suggests that the existence of diversity and estimated genetic parameters among landraces of rice that can be exploited in future rice breeding programs.

Oyster mushroom (Pleurotus oestratus) has outstanding flavor and taste with fan shaped pileus which is rich source of both macro and micro nutrients. It is of paramount importance to choose appropriate substrates in a given place to grow oyster mushroom successfully. The experiment was conducted at Bangaun, Lamahi, Dang, Nepal during 2018-19 to study the growth performance of oyster mushroom on locally available substrates as well as to find out the best substrate. The substrates used in the experiment were lentil straw, rice straw, wheat straw, maize stover, maize cob, along with the mix ratio of corn cob 1:3 with these substrates under factorial completely randomized design (CRD) design with four replications during winter season with an average daily temperature of 12-21°C and RH ranging from 80 to 90%. Among the tested substrate composition, significantly the lowest days (17.5 days) to complete spawn running was recorded on maize cob followed by lentil straw (22.5 days) while highest days (30.75 days) was required to complete spawn running on rice straw. The lowest time (25.50 days) for first fruiting initiation, the lowest time (33 days) for harvesting and the highest yield (2.47 kg) was revealed by lentil straw. The highest pileus diameter (6.81 cm) was recorded on wheat straw followed by rice and maize cob mix at 3:1 ratio (6.58 cm). Lentil straw was found the best substrate and rice straw mix with maize cob was more efficient as compared to rice straw only for the production of Pleurotus ostreatus mushroom.