Evaluation of radish genotypes with special study on sowing geometry at agricultural research institute, Tarnab, Peshawar

The research was carried out on the “Evaluation of Radish genotypes with special study on sowing geometry at Agricultural Research Institute, Tarnab Peshawar”. The experiment was laid out in randomized complete block design having three replications. The experiment comprised with two factors, one was sowing dates(19th Oct., 4th., Nov., and 19th Nov) and the other was different genotypes (Mino, Local Red and Local White). The data were recorded on Days to germination, Germination (%), Days to edible maturity, Number of leaves plant-1, Leaf length plant-1 (cm), Root length plant-1 (cm), Root diameter plant-1 (cm), root fresh weight (g), Plot weight (kg) and yield (t ha-1). Sowing dates significantly affected all yield parameters. Sowing of radish on 19th October has more number of Leaves (17.44 leaves) plant-1, Leaf length plant(22.611 cm), root length plant-1(24.058 cm), root diameter plant-1(3.12 cm) fresh root weight (503.95g), the maximum plot weight (50.90 kg plot-1) and higher yield (62.36t ha-1) was observed whereas the crop sown on 19th November showed the minimum days to germination (8.88 days), germination percentage (96.88%) and minimum days to maturity (53 days). Among genotypes Mino take minimum days to germinate(8.22 days), maximum germination percentage (99.22), minimum days to maturity (52.778), maximum number of leaves (19.44 leaves), leaf length (23.422 cm), greater root length (24.588 cm), maximum root diameter (3.53 cm), higher root fresh weight (536.62g), higher weight per plot (52.22 kg) and maximum yield (63.54t ha-1). The results emphasized that the suitable time of sowing for Mino genotype is 19th October for Peshawar.

Determination of salt tolerance levels and genetic relationships of Vicia sativa cultivars using gene targeted functional markers

The objectives of the present study were to determine salt tolerance levels of 12 different common vetch (Vicia sativa L.) cultivars at germination stage in the presence of 250 mM NaCl and to reveal genetic relationships based on gene targeted functional markers (GTFMs) associated with salt tolerance. The results revealed the presence of a significant genetic variation among the cultivars although s alt stress significantly reduced all germination parameters tested. The cultivar Ozveren was the most salt tolerant with 20.1% reduction in final germination percentage compared to control seeds while cultivars Alınoglu, Ayaz and Bakir did not germinate. The maximum delays in germination rate (G50 = 3.78 days) and synchrony (G10-90 = 3.45 days) were obtained from the cultivars Urkmez and Ozveren, respectively. The GTFMs provided a total of 53.1% polymorphism. The primers of MtSOS2 gene gave the highest numbers of alleles per primer pair while the highest polymorphism rate (77.8%) was obtained from the MtP5CS gene. The first three components of principal component analysis explained 57.63% of total variation. This study concluded that the cultivars determined to be salt tolerant and sensitive at germination stage distributed into three main clades determined by UPGMA analysis while the GTFMs associated with salt tolerance successfully determined the genetic relationships of common vetch cultivars.

Germination potential and methods for overcoming seed dormancy for domesticated and wild annatto populations after two years of storage

ABSTRACT: Annatto (Bixa orellana L.) is an arboreal species domesticated in Amazonia from its wild ancestor (B. orellana var. urucurana). Bixin extracted from its orthodox seeds is a natural dye widely used in the food industry. This study evaluated methods to overcome seed dormancy and determine the germination potential, comparing domesticated and wild annatto populations. Seeds from two domesticated-type populations and two families of a wild-type population, stored for two years after field collection, were submitted to five treatments to overcome dormancy: T1 - control; T2 - mechanical scarification (with sandpaper); T3 - mechanical scarification (with sandpaper) + immersion in water at 36 ºC overnight (12 hours); T4 - immersion in water at room temperature (23 ºC, on average) for 24 h; T5 - immersion in concentrated sulfuric acid (95 - 98%) for 15 min + running water for 3 min. Highly significant differences (P < 0.001) were observed in the germination percentage of annatto seeds between wild and domesticated types, and among the treatments tested. Domesticated types showed higher germination percentage (10 - 58%) over all treatments when compared to the wild type (0 - 44%). The best treatments were those performed with mechanical scarification. Given the simplicity, we concluded that mechanical scarification with sandpaper is a good alternative to overcome dormancy of annatto seeds.

Self-pollination of the orchid Cycnoches haagii from Brazilian Cerrado results in albino phenotype seedlings

Cycnoches haagii Barb. Rodr. is an epiphytic orchid very targeted by collectors, but no reference was found in the literature about its reproductive biology. Thus, the purpose of this study was to obtain initial information regarding pollination types and its influence on seed viability of this native orchid of the Brazilian Cerrado, in order to enable future propagation and preservation programs. Pollination among flowers of the same plant (geitonogamy) or different plants (xenogamy) were carried out. Seeds extracted from the capsules were sown in B&G medium, with full and half strength. Seeds from geitonogamic resulted in 25% of albino protocorms and consequently in albino seedlings. This phenomenon did not occur in seedlings derived from xenogamic pollination. Pigment analysis showed that even the albino seedlings presented chlorophylls and carotenoids, however, in significantly minor concentrations, 16% and 37% respectively, in relation to green seedlings. Geitonogamic and xenogamic pollinations resulted in C. haagii viable seeds with high germination percentage (90%) under in vitro conditions. The germination of seeds from xenogamic pollination resulted in chlorophyll or normal seedlings only, and can be recommended at conservation programs. On the other hand, although geitonogamic pollination should be avoided at conservation programs of this orchid species as it leads to albino seedlings, it showed a very interesting system to obtain seedlings with this phenotype, an interesting plant material to future investigation.

Statistical modeling for analyzing grain yield of durum wheat under rainfed conditions in Azad Jammu Kashmir, Pakistan

One of the most important traits that plant breeders aim to improve is grain yield which is a highly quantitative trait controlled by various agro-morphological traits. Twelve morphological traits such as Germination Percentage, Days to Spike Emergence, Plant Height, Spike Length, Awn Length, Tillers/Plant, Leaf Angle, Seeds/Spike, Plant Thickness, 1000-Grain Weight, Harvest Index and Days to Maturity have been considered as independent factors. Correlation, regression, and principal component analysis (PCA) are used to identify the different durum wheat traits, which significantly contribute to the yield. The necessary assumptions required for applying regression modeling have been tested and all the assumptions are satisfied by the observed data. The outliers are detected in the observations of fixed traits and Grain Yield. Some observations are detected as outliers but the outlying observations did not show any influence on the regression fit. For selecting a parsimonious regression model for durum wheat, best subset regression, and stepwise regression techniques have been applied. The best subset regression analysis revealed that Germination Percentage, Tillers/Plant, and Seeds/Spike have a marked increasing effect whereas Plant thickness has a negative effect on durum wheat yield. While stepwise regression analysis identified that the traits, Germination Percentage, Tillers/Plant, and Seeds/Spike significantly contribute to increasing the durum wheat yield. The simple correlation coefficient specified the significant positive correlation of Grain Yield with Germination Percentage, Number of Tillers/Plant, Seeds/Spike, and Harvest Index. These results of correlation analysis directed the importance of morphological characters and their significant positive impact on Grain Yield. The results of PCA showed that most variation (70%) among data set can be explained by the first five components. It also identified that Seeds/Spike; 1000-Grain Weight and Harvest Index have a higher influence in contributing to the durum wheat yield. Based on the results it is recommended that these important parameters might be considered and focused in future durum wheat breeding programs to develop high yield varieties.

The radicle emergence test and storage longevity of cucurbit rootstock seed lots

A study was carried out to test whether a single count of radicle emergence (RE test) would correlate with the storage potential of seed lots of cucurbit (C. maxima &times; C. moschata) rootstock cultivars. The RE test was performed by counting radicle emergence percentage between 26 and 100 hours of germination. Seed longevity was determined by storage at 75% relative humidity at 35&deg;C over 100 days, with seed survival curves constructed based on normal germination percentages. Ki (estimated initial viability in probits), &sigma; (standard deviation of the normal distribution of seed death in time) and p50 (time for viability to fall to 50%) were determined through probit analysis. Correlation analysis showed that RE counts particularly between 30 and 34 hours were highly (P &lt; 0.01) correlated with normal germination percentage, Ki and p50. It can be concluded that RE tests can be used as an indicator of subsequent seed lot longevity in cucurbit rootstock seed cultivars.

Overcoming dormancy in seeds of Dietes bicolor (Steud.) Sweet ex Klatt

Seminiferous propagation of Dietes bicolor is hindered by the probable physical and/or morphophysiological dormancy. The objective was to analyze the efficacy of different methods of overcoming dormancy in D. bicolor seeds to determine a possible pre-germination treatment for the species. Two experiments were conducted: (I) Evaluation of the breaking of physical dormancy, in which the treatments of mechanical scarification were carried using sandpaper #100; chemical scarification with sulfuric acid (H2SO4) for 5 and 10 minutes and immersion in hot water (70 ºC), also, for 5 and 10 minutes, were evaluated. The intact seed was considered a control. (II) Evaluation of morphophysiological dormancy, in which the seeds were submitted to combined treatments of stratification of hot temperature (20-35 °C) and/or cold temperature (9 ºC), distributed in periods of 0, 1, and 2 weeks, totalizing 9 treatments. In both experiments, germination percentage (G), germination speed index (GSI), and first count (FC) were determined, using a randomized block design, and evaluated by the Scott-Knott test at 1% and Dunnett’s test at 5%. The use of H2SO4 10 minutes induced 42% germination, 0.52 GSI, and 18% FC, but only FC was significantly different from the control. In the second trial, the treatment that spent only two weeks in hot temperatures (20-35 ºC) showed the highest germination (30%), compared to the control (G = 22%). These results provide relevant information for understanding the physiology of D. bicolor germination, in addition to contributing to the optimization of pre-germination practices for this important ornamental species.

Germination characteristics of plump and shriveled seeds of Tamarix ramosissima matured in different seasons

Tamarix ramosissima has bi-seasonal flowering and fruiting. Although the basic germination characteristics of T. ramosissima seeds have been evaluated, there is a lack of information about the effects of seed plumpness on germination. Effects of seed plumpness and season of maturity and light conditions on germination were tested. Plump seeds matured in spring or summer had similar size and pappus length. The size of plump seeds was significantly larger than that of shriveled seeds. Both types of seeds matured in summer germinated better than seeds matured in spring. Germination percentage of plump seeds was significant higher than that of shriveled seeds, especially for seeds matured in spring. Darkness significantly decreased the germination of seeds matured in summer. This study provides comprehensive information about the seed germination requirements of T. ramosissima and the results can be used in restoration of desert lands.

Role of L-Ornithine in Mitigation of Salt Stress In Allium Cepa L.

Effects of L-ornithine (150 mg/l) on the germination, seedling growth, mitotic index, chromosome aberrations and micronucleus frequency of Allium cepa L. bulbs germinated at 0.125 M salinity were studied. The radicle number of the group III bulbs germinated in the medium with ornithine alone as compared to ones of the group I (control) bulbs which germinated in distilled water medium. But, their germination percentage, radicle length and fresh weight were statistically the same as ones of the group I bulbs. Besides, the micronucleus frequency and chromosomal abnormalities in the root-tip meristematic cells of the group III bulbs showed increased germination compared to ones of the group I bulbs. However, their mitotic index statistically showed the same value as the group I bulbs. Salt stress significantly inhibited the germination and seedling growth of A. cepa bulbs. Moreover, it reduced the mitotic index in the root-meristem cells of the bulbs and fairly increased the number of chromosome aberrations and micronucleus frequency. On the other hand, the inhibitive effect of salt on the germination, seedling growth, mitotic index and micronucleus frequency was dramatically alleviated in varying degrees by ornithine application. But, it was ineffective in reducing the detrimental effect of salinity on the chromosome aberrations. The germination percentage, radicle lenght, radicle number, fresh weight, mitotic index, micronucleus frequency and chromosomal aberrations of the group II seedlings grown in 0.125 M salinity were 27%, 13.5 mm, 18.4, 7.1 g, 5.5, 18.3 and 60.8%, respectively while these values became 68%, 16.4 mm, 16.4, 10.5 g, 15.6, 7.6 and 74.8% in the group IV seedlings treated with L-ornithine. Bangladesh J. Bot. 50(4): 1165-1171, 2021 (December)

Enhancing Germination of Seeds of Cassia abbreviata and Senegalia nigrescens Using Pre-Sowing Seed Treatments in Botswana

Cassia abbreviata and Senegalia nigrescens are indigenous trees found in North and Central regions of Botswana. However, inadequate knowledge of their silviculture and decline in population due to deforestation, expanding settlements, infrastructure and agriculture are major threats to most indigenous tree species in Botswana. Like many indigenous tree species, Cassia abbreviata and Senegalia nigrescens are slow-growing and are threatened by overexploitation for numerous uses. Because of the increased demand for medicinal uses, medicinal species such Cassia abbreviata are rapidly disappearing in many habitats and threatened to extinction. This study assessed the response of pre-sowing treatment methods on quiescency and germination of seeds of Cassia abbreviata and Senegalia nigrescens tree species found in semiarid Savanna Ecozone of Botswana. Pre-sowing treatment included immersion in 98% undiluted sulfuric acid (H2SO4) for 15, 30, 45 and 60 minutes, submergence in boiling water for one, two, three minutes and submerged in warm water for 24 hours, mechanical scarification of the seed coat and control. ANOVA showed that there is a highly significant difference (P < 0.0001) among the treatments of C. abbreviata in seed germination and no significant difference among the treatments of S. nigrescens. The highest germination percentage of C. abbreviata seeds was 81%, which was found from seeds immersed in H2SO4 for 30 minutes, while for S. nigrescens seeds, the highest germination percentage was 99%, which was found from seeds treated with mechanical scarification and those immersed in H2SO4 for 15 and 45 minutes. The objective of this study is to determine the effect of pretreatment methods on germination of C. abbreviata and S. nigrescens seeds. Based on these results, we recommend sulphuric acid and mechanical scarification as suitable seed pre-sowing treatments for enhancing the germination of C. abbreviata and S. nigrescens, respectively.