Primary Spikes Research Articles

Growth and yield performance of castor hybrids under different methods of planting and fertility levels in North Gujarat Agro-climatic region

A field experiment was conducted to evaluate the yield performance of castor hybrids under different methods of planting and fertility levels at Agronomy Instructional Farm, C P College of Agriculture, Sardarkrushinagar, Gujarat in loamy sand soil. The experiment consisted eight treatment combinations with two hybrids (GCH 7 and GCH 8), two planting methods (Direct seed sowing and Transplanting) and two fertility levels(75% RDF and 100% RDF) were undertaken in randomized block design with factorial concept and replicated four times. Significantly higher number of capsules (88.63) on primary spike, seed yield per plant (686.30 g), 100-seed weight (32.49 g), number of spikes (20.01) per plant, seed yield (3220 kg/ha) and stalk yield (5340 kg/ha) were recorded with GCH 8 hybrid. In plantingmethods, significantly higher number of capsules (89.09) on primary spike, seed yield per plant (688.65 g), number ofspikes (19.60) per plant, seed yield (3230 kg/ha), stalk yield (5361 kg/ha) and available P2O5 (48.7 kg/ha) and S (13.01 mg/kg) after harvest of crop were recorded under direct seed sown castor. 100% RDF registered significantly higher plant height (86.14 cm) at harvest, number of nodes (18.58) per plant, number of capsules (88.60) on primary spike, length of primary (74.57 cm) spikes, seed yield per plant (688.53 g), 100-seed weight (32.00 g), number ofspikes (19.66) per plant, seed yield (3190 kg/ha), stalk yield (5281 kg/ha) and available N, P2O5and S (156 kg/ha, 49.8 kg/ha and 13.35 mg/kg, respectively).

Genetic variability studies of major yield components in segregating population derived from pistillate lines of castor (Ricinus communis L.)

A segregating population was developed by crossing two pistillate (female) lines of castor viz., IPC-23 and IPC-21. Population behavior was studied to understand the variability for major yield and yield components. The distribution of node number, plant height and seed yield were deviated fromnormal distribution and it was positively skewed with significant leptokurtic curve indicating that the two parents with high seed yield were selected for population development. Positive skewness indicates that the plants with exceptionallyhigh seed yield were isolated from the population. Difference between phenotypic co-efficient of variation (PCV) and genotypic co-efficient of variation (GCV) was very low to moderate for major yield components viz., number of effective spikes per plant, number of nodes to primary spike, plant height, total spike length and effective spike length of primary indicating that phenotypic selection can be effectively used for yield improvement. High heritability and genetic advance over mean (GAM) indicated the role of additive gene action for plant height and total/effective primary spike length. Correlation of number of nodes up to the primary spike with plant height up to primary spike, and total/effective spike length was positive indicating the possibility of short-statured, early pistillate selections with long primary spikes in castor.

Mathematical Modeling of the Information Process in the Angular Acceleration Biosensor

A mathematical model of the formation of output information in a biosensor of angular acceleration is presented. The functional and numerical parameters of the model have been determined by results of experiments made in 2001–2008. A comparison with the mathematical model of J. M. Goldberg and C. Fernandez (1971) describing the change in spike frequency of the primary afferent neuron spikes in response to an angular acceleration of the head as it turns around a vertical axis is carried out.

Enhanced N-metabolites, ABA and IAA-conjugate in anthers instigate heat sensitivity in spring wheat.

Unraveling the metabolic and phytohormonal changes in anthers exposed to heat stress would help identify mechanisms regulating heat stress tolerance during the sensitive reproductive stage. Two spring wheat genotypes contrasting for heat tolerance were exposed to heat stress during heading in controlled environment chambers. Anthers were collected from main and primary spikes for metabolic and phytohormonal profiling. A significant reduction in seed set (38%), grain number (54%) and grain weight (52%) per plant was recorded in the sensitive (KSG1177) but not in the tolerant (KSG1214) genotype under heat stress compared to control. Anther metabolite accumulation did not vary quantitatively between main and primary spikes. Hierarchical clustering of the genotypes and treatments using metabolites and phytohormones revealed a distinct cluster for KSG1177 under heat stress from that of control and KSG1214. A significant increase in N-based amino acids, ABA, IAA-conjugate and a decrease in polyamines and organic acids were observed in wheat anthers exposed to heat stress. Unlike KSG1214, a significantly higher accumulation of amino acids, ABA and IAA-conjugate in anthers of the sensitive KSG1177 was recorded under heat stress. These findings provide the rationale and direction towards developing molecular markers for enhancing heat stress tolerance in wheat.

Standardization of procedure for assessing terminal drought stress tolerance induced by foliar spraying of potassium iodide and identification of promising castor germplasm using the developed procedure

Castor cultivated as a rainfed crop in southern India experiences terminal drought stress with cessation of monsoon. Stem reserves act as an important source of carbon for the seeds getting filled when photosynthesis is inhibited by drought and therefore, the ability to mobilize stemreserves towards economic yield is an important trait in selection for terminal drought tolerance. Potassium iodide (KI), a chemical contact canopy desiccant induces leaf desiccation by reducing chlorophyll content and can be used to simulate the conditions of terminal drought stress. This property could be employed for assessing the genotypic variability for stem reserve mobilization trait. During kharif 2015-16, in RG 1826, a genotype that had been identified earlier for root and drought tolerance, KI was sprayed @ 0.2-1.0% at 50% filling of capsules on primary spikes or 1.0-3.0% at 50% filling of capsules on tertiary spikes separately as two sets of foliar sprays. KI spray @1.0% at both the stages recorded total leaf desiccation, less seed yield reduction in primary (16%) and tertiary (29%) order spikes. Hence, 1.0% KI was taken as the optimum concentration to screen castor genotypes for terminal drought stress tolerance. During late rabi 2016-17, 12 germplasm lines with known drought tolerance (moisture stress induced between 30 and 90 DAS) ability and better root growth characters along with two checks were sown and at 100 DAS, KI was sprayed @ 1.0%. Four genotypes, viz., RG82, RG89, RG111, RG1437 with high stem reserve mobilization characterized by <30% reduction in total seed yield and <20% reduction in HI were identified as promising for terminal drought tolerance.

Quantifying the Impact of Heat Stress on Pollen Germination, Seed Set, and Grain Filling in Spring Wheat

Exposure to temperatures ≥30°C during flowering and grain filling stages can negatively affect seed set and seed weight in spring wheat (Triticum aestivum L.). The screening of a large set of germplasm under hot wheat growing environments (Indo‐Gangetic Plain in India) led to the identification of promising heat‐tolerant genotypes. The selected set of 28 diverse spring wheat genotypes were exposed to heat stress (34/16°C day/night temperatures) for 10 d during flowering and for 30 d during grain filling to quantify genetic variability in pollen germination, photosynthesis, and yield parameters under controlled‐environment conditions. Pollen grains collected immediately at anthesis (between 0530 and 0630 h) were incubated on liquid in vitro pollen germination media. Averaged across wheat genotypes, a significant reduction in pollen germination (39.9%, P < 0.001) was recorded from plants exposed to heat stress. Heat stress for 10 d during flowering induced significant reduction in seed number (15.4 and 23.0%) and seed weight (32.3 and 34.6%) on main and primary spikes, respectively, compared with the control. Heat stress during grain filling had a more pronounced impact on seed weight (16 and 22%) than seed number (2.7 and 9.3%) in main and primary spikes, respectively. Genotypes KSG025 and KSG1214 with higher seed number, seed weight, and harvest index and appreciable pollen germination under heat stress were identified as candidate donors for simultaneously enhancing flowering and post‐flowering heat tolerance in spring wheat.

Genetic architecture studies of yield and its components in castor

ABSTRACT Generation mean analysis implies to study genetics of seed yield and its components in castor (Ricinus communis L.) through generation mean analysis. The additive-dominance model was found adequate for days to maturity of primary spikes in cross I (AKC-1 x RG550), effective length of primary spikes in cross II (48-1 x RG550) and effective length of secondary spikes and number of secondary spikes in cross III (Aruna x RG550). Either dominance gene action or both additive and dominance gene actions were observed to be significant indicating the role of non additive component in the inheritance of most of the characters studied while only additive gene action along with epistatic interaction components were noted for effective length of secondary spikes in the cross I (AKC-1 x RG550) and number of capsules on primary spikes in the cross III (Aruna x RG550).

Heat Stress during Flowering Affects Time of Day of Flowering, Seed Set, and Grain Quality in Spring Wheat

ABSTRACTFlowering in wheat (Triticum aestivum L.) is highly sensitive to heat stress. Eleven spring wheat genotypes were exposed to heat stress (34/16°C, day/night temperature) during flowering to investigate the impact on time of day of flowering, seed set, grain yield, and quality under controlled environment chambers. In general, all 11 wheat genotypes recorded peak flowering during cooler hours of the day (i.e. either early in the morning or late in the evening). The trend was more pronounced under heat stress, providing first evidence of an alternative mechanism (i.e. heat escape in wheat minimizing damage during flowering). On average, significant reduction in net CO2 assimilation (17%), starch (25%), and protein content in grain (21%), seed set (7–19%), kernel weight (11–15%), and grain yield (22–38%), but with 17% increase in flag leaves proline concentration, was recorded under heat stress over control. The negative impact of heat stress on seed set was greater among the primary spikes than for the main spike. This differential impact is mainly attributed to limited plasticity of early reproductive processes such as gametogenesis to escape heat stress, unlike heat escape phenomena observed at flowering. KSG1203 and KSG41 exhibited heat escape strategy, whereas KSG1194 emerged as a true heat‐tolerant line. Systematic characterization of time of day of flowering to introduce the heat escape trait and developing heat tolerance strategies for early reproductive stages in ongoing wheat breeding programs is an ideal strategy to minimize heat stress damage.

Genetic analysis of yield and its biometric traits in castor (Ricinus communis L.)

The genetics of seed yield and its components was studied in castor (Ricinus communis L.) utilizing three crosses viz., AKC-1 x RG1636 (Cross - I); Aruna x RG1636 (Cross-II) and AKD-1 x RG1636 (Cross-III) through generation mean analysis. The additive-dominance model was found to be adequate for days to maturity of primary spikes in cross II (Aruna x RG1636) indicating the absence on non- allelic interactions. Additive (d) gene actions along with epistatic gene interactions were found to be significant for effective length of secondary spikes, oil content in the cross I (AKC-1 x RG1636); total number of capsules, 100 seed weight in the cross III (AKD-1 x RG1636), while rest of the characters were found to be governed by non additive gene actions. The classification of gene actions showed the importance of duplicate type of gene action for most of the characters in all the three crosses. Breeding procedures involving either multiple crosses or biparental crosses may be resorted to get transgressive segregants.

CONTRIBUTION OF PRIMARY SPIKES VS TILLERS TO TOTAL DEOXYNIVALENOL IN HARVESTED GRAIN OF WHEAT AND BARLEY

Formation of higher number of tillers is desirable for higher grain yield in both wheat and barley; ti llers have delayed physiological development. Studies addressing the contribution of secondary tillers in fi nal DON concentration for wheat and barley are limited. This project aims to improve our understanding of the relationship between FHB symptoms and DON concentration by examining the contribution of primary spikes and secondary tillers as it relates to the f inal DON concentration. Experiments, established as splitsplit plot design with five replications, was be co nducted in South Dakota with moderately resistant a nd susceptible cultivars of each spring wheat, winter wheat and barley. Two inoculation time treatments was applied; at the anthesis of primary spikes (Feekes 10.5) and at anthesis of tillers (Feekes 11.2). Pri mary spikes (inoculated at Feekes 10.5) and tillers (ino culated at Feekes 11.2) were harvested separately, analyzed for visually scabby kernels and deoxynival enol following standard protocols. Levels of DON were statistically higher in main heads of barley and sp ring wheat in each cultivar compared to its tillers . In winter wheat, though there was higher DON level in tillers than main heads in each cultivar, it was not stati stically different. Based upon our result, it is suggested t hat cultivars with high tillers number should be se lected in breeding programs to develop cultivars with high yi eld and low DON. Similarly, planting density of wheat and barley can be adjusted such that it will result in higher numbers of tillers, increasing tillers propo rtion that might lower DON concentration in final harvest.

Field Screening of Promising Castor Cultures against Capsule Borer, Conogethes punctiferalis and Leafhopper, Empoasca flavescens

Studies were carried out on castor at Tapioca and Castor Research Station, Yethapur, Salem District, Tamil Nadu to find out the resistant sources against capsule borer and leafhoppers Among the eight entries screened, capsule damage ranged from 0 to 11.5 % in the primary spikes as against 35.7 % in the check TMVCH 1. The damage ranged from 0 to 10.8 % in the secondary spikes as against 26.7 % in the check. Maximum capsule damage was observed in RG 3089 (11.5 and 10.8 % in the primary and secondary spikes, respectively), followed by RG 2813, which recorded 5.4 and 6.2 % capsule damage in the primary and secondary spikes, respectively. RG 2770, RG 2776, RG 2778 and RG 2849 were completely free from capsule borer damage.

Sodium channel inhibition by anandamide and synthetic cannabimimetics in brain

Anandamide is a prominent member of the endocannabinoids, a group of diffusible lipid molecules which influences neuronal excitability. In this context, endocannabinoids are known to modulate certain presynaptic Ca 2+ and K + channels, either through cannabinoid (CB1) receptor stimulation and second messenger pathway activation or by direct action. We investigated the susceptibility of voltage-sensitive sodium channels to anandamide and other cannibimimetics using both biochemical and electrophysiological approaches. Here we report that anandamide, AM 404 and WIN 55,212-2 inhibit veratridine-dependent depolarization of synaptoneurosomes (IC 50s, respectively 21.8, 9.3 and 21.1 μM) and veratridine-dependent release of l-glutamic acid and GABA from purified synaptosomes [IC 50s: 5.1 μM (L-glu) and 16.5 μM (GABA) for anandamide; 1.6 μM (L-glu) and 3.3 μM (GABA) for AM 404, and 12.2 (L-glu) and 14.4 μM (GABA) for WIN 55,212-2]. The binding of [ 3H]batrachotoxinin A 20-α-benzoate to voltage-sensitive sodium channels was also inhibited by low to mid micromolar concentrations of anandamide, AM 404 and WIN 55,212-2. In addition, anandamide (10 μM), AM 404 (10 μM) and WIN 55,212-2 (1 μM) were found to markedly block TTX-sensitive sustained repetitive firing in cortical neurones without altering primary spikes, consistent with a state-dependent mechanism. None of the inhibitory effects we demonstrate on voltage-sensitive sodium channels are attenuated by the potent CB1 antagonist AM 251 (1–2 μM). Anandamide’s action is reversible and its effects are enhanced by fatty acid amidohydrolase inhibition. We propose that voltage-sensitive sodium channels may participate in a novel signaling pathway involving anandamide. This mechanism has potential to depress synaptic transmission in brain by damping neuronal capacity to support action potentials and reducing evoked release of both excitatory and inhibitory transmitters.

Lateral geniculate nucleus unitary discharge in sleep and waking: state- and rate-specific aspects.

The relationship between behavioral state, discharge pattern, and discharge rate was investigated in 26 lateral geniculate nucleus (LGN) units recorded in cats in the dark during waking (W), synchronized sleep (S), and desynchronized sleep (D). A distinctive state-dependent discharge pattern was the presence of stereotyped bursts of 2-7 spikes that occurred in 63% of the units. These bursts were most frequent in S, much less frequent in D, and rarely occurred in W. Lack of association with discharge rate changes between states showed the bursting to be a true state-dependent phenomenon. A burst consisted of 2-7 spikes, with each successive interspike interval being longer than the preceding one; in the 200 ms prior to burst occurrence, discharge probability decreased markedly. This structure of burst organization suggested a model of generation wherein each burst was caused by a unitary event of varying intensity, perhaps a rebound following a hyperpolarization. Spectral and autocorrelational analyses showed bursts occurred rhythmically in three cells at a frequency of 3-4 Hz and in two cells at a frequency of 10-12 Hz, indicating a possible linkage with slow-wave generators. While the number of bursts in the various behavioral states was a state-dependent phenomena, other aspects of discharge pattern were shown to be rate dependent. To evaluate discharge pattern apart from the occurrence of bursts, a "primary event spike train" was formed; this consisted of individual spikes and the first spike of each burst. This analysis showed that, within S, the probability of burst occurrence was highest when the primary spike rate was low. Quantitative analyses showed that first-order pattern measures (the form of the interspike interval histogram, IH) were dependent on the mean interspike interval (ISI, the inverse of mean rate). This association explained 83-89% of the variance in a power series approximation of IH form. Joint interval histograms (JIH) were used to evaluate the signature of bursts and of the form of the primary spike train. As with interval histograms, the main features of the form of the primary spike JIH were dependent on the primary spike rate. Thus, we concluded that first- and second-order discharge patterns of primary events were rate dependent and not state dependent. Our data are compatible with a model where in the absence of retinal input, the frequency of LGN primary spikes over behavioral state changes is largely determined by brain stem reticular formation input.(ABSTRACT TRUNCATED AT 400 WORDS)

The independence of closely spaced discrete experimental spike foci.

Stable spike foci generated by weak penicillin solutions had a minimal area of distribution of 12.5 mm2. Two foci separated by 4 mm on the same gyrus were consistently dependent and simultaneous. An area of "positive surround" between the two spikes did not prevent dependency. This contradicts the hypothesis that "positive surround" prevents spreading of epileptiform discharges. Spike foci separated by 6 mm were almost always independent. Bursts of afterdischarges remained independent if the primary spikes were independent. Postafterdischarge suppression and spreading depression of Leao affected independent spike focus selectively. These experiments suggest that cross-talking between cortical columns is limited to column 1 to 2 mm apart.

Study of Chlorophyll Mutants in IR. 8 Rice

The frequency of chlorophyll mutations as number of mutations per 100 M; spikes was as efficient as the number of mutants per 100 M. plants. The relationship between dose and frequency remained the same irrespective of the method of estimation of mutation frequencies. The frequencies decreased at high doses even when estimated on My plant basis. The frequency of chlorophyll mutation in gamma irradiation increased upto the middle dose and thereafter followed an inconsistent trend whereas. in EMS treatments the frequency increased with increase in dosage. The rate of mutation was higher in primary spikes than the lust and second formed spikes. Induced chlorophyll mutation spectrum differed between gamma rays and EMS. Albing was the most fre quent type following irradiation while xantha was predominert with EMS treatments.

Comparison of direct cerebral and cerebellar cortical responses in the cat

Surface-evoked cerebral and cerebellar responses were compared in 35 cats. Single stimuli and 1-second trains (6 and 20/sec.) were used. Effects of gamma aminobutyric acid (GAB) applied to the cortical surface and of Nembutal and procaine injected intravenously were studied. Response of cerebral cortex to a single shock shows at least four components: initial negative spike, second negative wave, after-positivity, and slow negativity. Cerebellum shows only the initial negative spike and the slow negativity, second negative and after-positivity components being absent. In both cerebrum and cerebellum slow negativity shows summation with serial stimulation. Application of GAB to the cerebellar surface causes replacement of the negative spike by a positive one and a concurrent reduction in amplitude of slow negativity. In cerebral cortex Nembutal produces a striking augmentation of singly or serially evoked slow negativity, but marked amplitude reduction or reversal to positive polarity of the serially evoked primary spikes. By contrast procaine abolishes summed slow negativity of cerebral cortex leaving serial spikes unaffected. In the cerebellum Nembutal and procaine have no effect upon the direct cortical response at dosage sufficient to produce cerebral alterations. Thus synaptic activity signaled by the responses studied appears to be more susceptible to Nembutal and procaine in cerebrum than in cerebellum.