Primary Tillers Research Articles

Effect of Productive Tillers on Seed Yield and Seed Quality of Sorghum (<i>Sorghum bicolor L</i>.) Varieties in Assosa District, Western Ethiopia

Poor management of sorghum tillers is a significant problem in the Benishangul-Gumuz region of Ethiopia, affecting seed yield and quality. An experiment was conducted to determine the impact of sorghum productive tillers on seed yield and quality. The study involved two Sorghum varieties (Assosa-1 and Adukara) and three plant types per spot. The treatments were aligned as RCBD and CRD in factorial combination, replicated three and four times for field and laboratory experiments respectively. Varieties influenced TSW (P < 0.0001), Number of tiller influenced by number plants head matured for seed production (P ≤ 0.0001), plants height (P ≤ 0.0004), The interaction effects of varieties and number of tillers per plant influenced yields, Panicle length (P < 0.0001). For laboratory experiments varieties influenced Speed of germination (P < 0.0001), number of Dead seeds (P < 0.0001). Number of tiller influenced Speed of germination (P < 0.0001), number of Dead seeds, shoot length (P < 0.004), Vigor index one and Vigor index two (P≤0.05). The interaction effects of varieties and number of tillers per plant influenced Standard germination (P < 0.001). The main shoot plants had the highest number of fertile sorghum heads (86.5), followed by primary tillers (27.08). Secondary tillers had the highest plant height (96.52 cm). The main shoot plant yielded more seeds than primary and secondary tillers, with the shoot exceeding these yields by 302.96% and 1333%, respectively. Primary and secondary tillers had higher percentages of dead seeds than the main shoot plant, 53.5% and 45.2%, respectively. The primary and secondary tillers experienced a decline in seedling vigour index one over different periods, while the main sorghum plant varieties, Adukara and Assosa-1, showed an upward trend. The germination percentages of the primary and secondary tillers were less than the 85% Ethiopian seed standard requirement. Because sorghum tillers lower seed quality, they should be eliminated for seed production. If sorghum is grown for grain production, secondary tillers have the benefit of raising overall yield production.

Phenotypic variations of three upland rice (<i>Oryza sativa</i> L.) genotypes

This study was conducted to assess the phenotypic variations of three rain-fed upland rice genotypes (Faro 59, 64, and 'Art'). The study was conducted at the Teaching and Research Farm of Akwa Ibom State University, Oruk Anam L.G.A., in Akwa Ibom State, Nigeria, from August- November 2021. The three upland rice genotypes were planted in a plot using a randomized complete block design in four replications. Data were analyzed using a one way analysis of variance, and means separation was done using the Fisher's Least Significance Difference. Results showed significant differences in plant height at 10 weeks after planting. Faro 64 and Art had the highest mean heights of 100.15 cm and 'Art' had 97.82 cm, while Faro 59 had the least mean height of 92.95 cm respectively. There were significant differences in primary number of tillers/plant among the three rice cultivars. Faro 59 had the highest mean primary tillers-4 tillers/plant. Similarly, Faro 59 had the highest mean values for other traits in order of: panicle weight-3.34 g; 100 grain weight- 2.90 g; and grain yield-4.2 tons/hectare. The results of this study proved that Faro 59 had a greater advantage over 'Art' and Faro 64 with respect to most phenotypic traits (grain weight, panicle weight and primary tiller numbers/plant), and therefore is recommended for further research in this study area.

Insect Herbivory on Main Stem Enhances Induced Defense of Primary Tillers in Rice (Oryza sativa L.).

Clonal plants are interconnected to form clonal plant networks with physiological integration, enabling the reassignment as well as sharing of resources among the members. The systemic induction of antiherbivore resistance via clonal integration may frequently operate in the networks. Here, we used an important food crop rice (Oryza sativa), and its destructive pest rice leaffolder (LF; Cnaphalocrocis medinalis) as a model to examine defense communication between the main stem and clonal tillers. LF infestation and MeJA pretreatment on the main stem for two days reduced the weight gain of LF larvae fed on the corresponding primary tillers by 44.5% and 29.0%, respectively. LF infestation and MeJA pretreatment on the main stem also enhanced antiherbivore defense responses in primary tillers: increased levels of a trypsin protease inhibitor, putative defensive enzymes, and jasmonic acid (JA), a key signaling compound involved in antiherbivore induced defenses; strong induction of genes encoding JA biosynthesis and perception; and rapid activation of JA pathway. However, in a JA perception OsCOI RNAi line, LF infestation on main stem showed no or minor effects on antiherbivore defense responses in primary tillers. Our work demonstrates that systemic antiherbivore defense operate in the clonal network of rice plants and JA signaling plays a crucial role in mediating defense communication between main stem and tillers in rice plants. Our findings provide a theoretical basis for the ecological control of pests by using the systemic resistance of cloned plants themselves.

Supplemental irrigation at jointing improves spike formation of wheat tillers by regulating sugar distribution in ear and stem

Irrigation at jointing increases spike numbers at wheat harvest, but the mechanisms underlying increased tiller spike formation rate (SR) during wheat production caused by irrigation have remained unclear. We therefore designed the supplemental irrigation (SI) treatments at jointing in which SI was received (SIJ) or did not receive (NSI) by wheat, and analyzed the morphological differentiation of young ears and physiological responses of young ears and stems to SI. Results shown that SIJ relative to NSI mainly improved the SR of the first primary tiller (T1) and second primary tiller (T2), which significantly increased the grain yield. The tillers SR positively correlated to the soluble sugar and sucrose contents in young ears, but negatively correlated to that in stems. SIJ significantly increased the soluble sugar and sucrose contents in young ears and reduced that in stems in both the main stem (MS) and tillers. Compared with MS, the young ear differentiation of T1 and T2 tillers that can form spikes was always behind by 0–2 developmental periods between jointing and flowering. Although SIJ decelerated the young ears differentiation of the MS and the T1 tiller, the increased sugar content in young ears causing a significant increase in grain numbers. Moreover, SIJ positively regulated the young ear differentiation of T2 tiller with more sucrose contained in young ears and less in stems to narrow gaps in young ear differentiation between T2 tiller and MS. Some T1 and T2 as well as other high-position tillers composed invalid tillers, where young ears mostly ceased differentiating at the stages of glume primordium present to carpel primordium present, and contained significantly less sugar than effective tillers. Significant morphological differences in young ears and nutritional physiological differences in tillers led to high-position tillers that were difficult to convert into effective tillers even under favorable conditions by SIJ. Overall, tillers can be converted into effective spikes by increasing sugar metabolism in young ears via SIJ when the discrepancy in young ear differentiation does not exceed two developmental stages compared to MS.

Stem lodging parameters of main culm and primary tiller of upland rice cultivars as affected by nitrogen fertilizer rates

The Ceylon Journal of Science is a peer-reviewed journal published quarterly by the University of Peradeniya, Sri Lanka in March, June, September and December. It is aimed at publishing high quality research articles on topics related to different disciplines in Science. The journal accepts original research articles, book reviews, reviews and mini-reviews, short communications, opinions, research notes, and commentaries and notes. The Journal has its own website https://site.pdn.ac.lk/cjs/. The journal strictly adheres to publication ethics as emphasized by the Committee on Publication Ethics (COPE). It is indexed in Sri Lanka Journals Online (SLJOL), Directory of Open Access Journals (DOAJ), Google Scholar and Zoological Records. According to the Google Scholar;H5-Index: 12H5-Median: 15According to the Exaly (1970 – 2021);Impact Factor: 0.6 (top 19%)Extended IF: 0.6 (top 19%)H-Index: 8 (top 28%)Citations/paper: 1.42

Maize straw mulching with uniconazole application increases the tillering capacity and grain yield of dryland winter wheat (Triticum aestivum L.)

Improvements in wheat tillering in dry-land farming systems can be achieved by reducing soil water loss by straw mulching and enhancing the capability of wheat roots to capture soil water and N. However, the effects of the application of maize straw mulching in combination with uniconazole application on wheat tillering is not yet investigated. Field experiments were conducted during 2017–2018 (dry, 167 mm) and 2018–2019 (favorable, 222 mm) to investigate the combined effects of uniconazole (0 and 10 mg kg-1) and maize straw mulching (0 and 7500 kg ha-1) on soil water and root distribution, phytohormone signal transduction, total N uptake, plant N nutrition, tillering capability, and the expression of critical genes and metabolites in response to wheat tillering. Compared with no mulch control, straw mulching combined with uniconazole application increased soil moisture content and root length in the 0–20 cm soil layer and thereby increased total N uptake. Owing to allometric increases in aboveground N content and plant dry mass, uniconazole application combined with straw mulching increased the dry mass per kg N uptake and N nutrition index in the tillering and stem extension stages. Improved N nutrition index led to higher tiller emergence rate and tiller occurrence rate of first primary tillers and thus increased the number of fertile spikes and grain yield. Multi-omics integration analysis revealed that the increased tillering capability was associated with abscisic acid and gibberellic acid-mediated phenylpropanoid biosynthesis and glycerophospholipid metabolism because of their critical roles in lignin biosynthesis and the maintenance of cell membrane integrity in tiller node cells. The collective results indicate that maize straw mulching combined with uniconazole application improved the capability of wheat roots to capture soil moisture and N in addition to increasing lignin biosynthesis, ultimately enhancing tillering capability and grain yield of dryland winter wheat.

Hypersensitive response and induced resistance in rice gene differentials against biotype 1 of Asian rice gall midge, Orseolia oryzae at Mandya, Karnataka

Hypersensitive reaction (HR) and induced resistance were noticed in resistant rice genotypes infested by gall midge. Detailed observations on Phalguna (Gm2 gene), Abhaya (Gm4 gene), ARC 5984 (Gm5 gene) infested with gall midge biotype 1 revealed that the infestation triggered HR in the plant, leading to extensive tissue necrosis at the apical meristem and browning of central leaf. This was followed by maggot mortality and premature tillering. In susceptible genotypes this phenomenon was not evident. HR leading to necrosis is fatal to host plant but premature tillering was observed. Further, the secondary tillers were infested subsequently with the gall midge biotype 1 eggs at 7, 14, 21 and 28 days after primary infestation, and maggots failed to establish and cause silver shoot. However, HR was observed 6 days after secondary tiller infestation, when the primary tillers were infested 28 days after. But cent per cent maggot mortality was observed, regardless of the time interval between infesting primary and secondary tillers in all the HR + plants. Thus, the HR is not confined to the tillers of primary infestation but it also triggers systemic acquired resistance in other tillers in Phalguna, Abhaya and ARC 5984, whereas, in W1263 (Gm1 gene), HR+ was not evident but antibiotic effects were observed along with maggot mortality.

Physiological and sanitary quality of ryegrass seeds submitted to different defoliation frequencies

ABSTRACT: This study determined the effect of different defoliation frequencies in a long-cycle ryegrass cultivar on yield components and the physiological and sanitary quality of seeds. Four defoliation frequencies were applied (without, one, two, and three defoliations). The time between defoliations was 350 degree-days. At the first, second, and third defoliation time, the plants were 15 cm, 20 cm, and 35 cm, respectively, and were lowered to half their height. The yield components and plant structure were evaluated through the tillers, along with the physiological quality of the seeds, which was verified by germination tests, first germination count, accelerated aging, tetrazolium test, field emergence, and weight of a thousand seeds. For the sanitary quality analysis, the percentage (%) of fungi incidence in the seeds was verified. The second defoliation determined the seeds’ high physiological and sanitary quality due to the higher amount of primary and secondary tillers produced concerning the other treatments. However, there was no significant difference for the third defoliation since the aerial tillers issued the same quality of seeds originated from primary and secondary tillers. The average incidence of fungi such as Colletotrichum sp., Fusarium sp., Phoma sp., and Dreshslera spp. was lower in ryegrass plants subjected to three defoliations.

The mechanical origin of the radial shape in distichous phyllotaxy grass plants

Abstract Three-dimensional plant shapes are influenced by their phyllotaxy, which plays a significant role in their environmental adaptation. Grasses with distichous phyllotaxy have linearly aligned culms and usually have vertical fan-like shapes. Counterintuitively, some distichous phyllotaxy grasses have radial shapes. Here, we investigate the organ-level mechanism underlying radial shape development in the distichous phyllotactic wild rice species (Oryza rufipogon). Detailed time-course phenotyping and three-dimensional micro-computed tomography showed that changes in the elevation angle in the main culm and azimuth angle in the primary tillers contribute to radial shape development. To infer the mechanical basis of the shape change, we simulated the movements of culms controlled by different kinematic factors. The computational models predicted that the combination of movements, including that controlled by negative gravitropism, produces the overall radial shape. This prediction was experimentally assessed. The analysis using a near-isogenic line of the gene, PROG1 for prostrate growth and the gravitropic mutant (lazy1) showed an association between genes and our model parameters. Our findings provide a simple, yet substantial, kinematic model for how the shape in distichous phyllotaxy plants changes as part of their adaptation to the surrounding environment.

Understanding the Regulatory Mechanisms of Rice Tiller Angle, Then and Now

Rice is one of the most important crops worldwide, whose yield is vital to human nutrition in the context of a rapidly growing world population. Plant architecture significantly affects grain yield, which is to a large extent determined by tiller angle and tiller number. Tiller angle is the angle between the primary tiller and the main culm. Its regulation is complex and is influenced by multiple environmental and genetic factors. This review provides an overview of the regulation of tiller angle in rice, with particular focus on the roles of the growth environment and method of cultivation; phytohormones such as auxin, gibberellins, and strigolactones; gravity; and genes related to the control of tiller angle. The major research foci and the outlook for research into the regulation of tiller angle in rice are discussed.

Source-sink relationships of wheat plants obtained by the application of systemic herbicides

Abstract: The objective of this work was to evaluate the potential of solute translocation among stems of wheat (Triticum aestivum), by the application of the systemic herbicides clethodim and glyphosate. The experiments were carried out in greenhouse conditions, using wheat cultivars with contrasting potential for tillering, during the winter of 2017 and 2018 in Southern Brazil. Clethodim was applied on isolated stems, to evaluate the potential translocation of solutes from the first three tillers. Translocation was evaluated by the yield parameters on stem ears not treated with clethodim. Glyphosate was used to evaluate the potential translocation of solutes from late tillers. Translocation was evaluated by the assimilation of carbon in stems without the glyphosate treatment. When applied on isolated primary tillers, clethodim reduced yield parameters only in treated stems, which shows that the assimilates were targeting the main sink, in detriment of the other organs. There was a decrease in net carbon assimilation in stems without the glyphosate treatment at the first visible node stage. Glyphosate applied on late tillers, at anthesis, reduced even more net carbon assimilation in nontreated stems of the primary tillers of the BRS Parrudo wheat cultivar (low tillering). Well-developed late tillers show higher potential of solute translocation to the whole plant than the poor-developed ones.

Spike formation and seed setting of the main stem and tillers under post‐jointing drought in winter wheat

AbstractTo clarify the influence of post‐jointing drought on the ear‐bearing and seed‐setting characteristics of the main stem and tillers of winter wheat (Triticum aestivumL.), a pot experiment was conducted with cultivars “Shannong 29” (SN29) and “Heng 0628” (H0628), and five water regimes: mild drought (WR1) and severe drought (WR2) for 0–5 days after jointing, mild drought (WR3) and severe drought (WR4) for 0–10 days after jointing and adequate water supply as a control (CK). The present study focused on primary tillers (appear in the axils of main stem leaves: T1, T2, T3, T4, etc.), as well as on secondary tillers (appear from the bud in the axil of the prophyll: T10 and T20; appear in the axil of the first leaf of the primary tiller T1: T11). The yield components of tillers showed a downward trend with increasing tiller position and drought degree and duration, and the kernels per spike, single kernels weight and grain yield per spike of tillers T2, T3, T10 and T4 decreased more than those of the other tillers. These outcomes may be related to the spike developmental stages at the time of the drought period. Severe drought during the period from when the stamen primordium is first present (Waddington’s stage 4) to when the carpel extends around the three sides of the ovule (Waddington’s stage 5) significantly decreased the seed set of tillers, but short‐term (5 days) mild drought during this period and even a short‐term severe drought before Waddington’s stage 4 had little effect on the seed set of tillers. The ear‐bearing capacity of tillers was determined not only by the spike developmental stage, but also by the gap from the main stem and the competition of nutrition and space between tillers. Although the ear‐bearing rate of tillers T3 and T10 decreased rapidly after the short‐term mild drought, the increase in the ear‐bearing rate of tillers T20 and T11 effectively compensated for the loss of the number of spikes per plant. Therefore, the short‐term mild drought at the jointing stage had no significant effect on the grain yield of the two cultivars. The tillers T2, T3, T10 and T4 were sensitive to soil moisture in the jointing stage and had high plasticity. During this period, if timely irrigation improves soil moisture, it is expected to increase the ear‐bearing rate and seed set of these tillers, thereby increasing grain yield.

Role of nonproductive tillers as transient sinks of assimilates in wheat

ABSTRACT Although source–sink relationships in wheat are well studied, the performance of tillers as transient sinks is still unclear, especially under stress conditions. Thus, this work aimed to study the yield relationships of wheat stems in contrasting genotypes as affected by tiller treatment under stress conditions. Two experiments were conducted under greenhouse conditions using BRS Guamirim (high tillering) and BRS Parrudo (low tillering) wheat cultivars. Four tillering treatments were applied on late tillers in the first growing season (2016) and three in the second (2017): (i) free-tillering, (ii) detillering, (iii) physical suppression (only in the first season) and (iv) “spikes removal”. The main stem and the first four emitted tillers were considered as primary tillers. Plants were submitted to drought (2016) and defoliation stress (2017) at preanthesis. Intraspecific competition among tillers increased under drought stress conditions and decreased the plant performance. Nonproductive late tillers do not improve the performance of primary tillers of wheat plants under drought stress, mainly in high-tillering cultivars. The reduction on the thousand grain weight of only ‘Parrudo’ detillered plants indicates that assimilate remobilization from late tillers to primary tillers and main stem seems to be more effective in low-tillering cultivars.

Effects of supplemental irrigation at the jointing stage on population dynamics, grain yield, and water-use efficiency of two different spike-type wheat cultivars.

To solve the problems of yield reduction and low water-use efficiency (WUE) of winter wheat (Triticum aestivum L.) caused by winter and spring drought, a 2-year field experiment (2017-2019) was performed under movable shelter conditions with the large- and multispike cultivars Shannong 23 and 29, respectively, to explore the optimal supplemental irrigation regime. Three wetting layers were used for irrigation at the jointing stage: 0-10 cm (T2), 0-20 cm (T3) and 0-30 cm (T4). No irrigation at the jointing stage (T1) served as the control. Within a given cultivar, the soil water content in the 0-80 cm soil layers increased after irrigation, and the rate of tiller mortality decreased with increasing depth of the wetting layer used for irrigation at jointing. No significant differences were found between the T3 and T4 treatments in the photosynthetic rate (Pn) of the apical leaf of the main stem (O), the first primary tiller (I) and the fourth tiller (IV) after jointing. However, compared with the T3 treatment, the T4 treatment had a significantly higher transpiration rate (Tr) and lower instantaneous water-use efficiency (WUEleaf) of the apical leaf of the O and tillers I and IV. This eventually led to a decreasing WUE, although there was no significant change in the spike number or grain yield. These results indicated that moderate irrigation at jointing can effectively reduce the tiller mortality, improve the leaf Pn of the tillers, and increase the spike number and grain yield. However, excessive irrigation can significantly increase the leaf Tr of the tillers, lead to inefficient water consumption and significantly reduce the WUEleaf of the tillers and the WUE. Irrigation at the jointing stage brought the soil water content in the 0-20 cm profile to 100% of field capacity, making it the most suitable supplemental irrigation regime for both the large- and multispike cultivars in the North China Plain.

Tiller profile diversity of upland rice germplasm in ICABIOGRAD gene bank

Tillering ability is an important agronomic trait that determines the yield of rice. Tiller type in rice is categorized as primary, secondary and tertiary tiller which produces panicle at generative phase. Tillering ability as well as the tiller type varies between varieties, especially among germplasms. Our study aimed to identify the tiller profile diversity of upland rice germplasm in ICABIOGRAD Genebank. A total of 100 accessions of local upland rice varieties were planted in a randomized completely block design with two replications under greenhouse condition. The number of tiller from each type was observed weekly from 35 to 63 days after sowing (DAS). The result of the study showed that the number of primary tiller increased slowly from 35 DAS until 63 DAS. After 49 DAS there was no significant addition in secondary tiller number. Generally, the average mean number of tertiary tiller accross the accessions was far below compared to the number of primary and secondary tiller. The highest number of primary tiller, i.e. 8, was expressed by Pae Daye Indolobye (North Sulawesi), Padi Pulut Pute Iteung (East Kalimantan) and K. Puyuk (Central Kalimantan). Up to 22 secondary tillers were formed by Gadabung, a local upland rice variety from Central Kalimantan. Information on tillering ability of local upland variety will benefit rice breeder for selecting appropriate accessions as a gene source for breeding.

Primary-tiller panicle number is critical to achieving high grain yields in machine-transplanted hybrid rice

The development of machine-transplanted hybrid rice is a feasible approach to meet the needs of both high grain yield and high labor efficiency in China, but limited information is available on the critical plant traits associated with high grain yields in machine-transplanted hybrid rice. This study was carried out to identify which type of culms (i.e., main stems and primary and secondary tillers) and which yield components of this culm are critical to achieving high grain yields in machine-transplanted hybrid rice. Field experiments were conducted with two hybrid rice cultivars grown under two densities of machine transplanting in two years. Results showed that total grain yield of main stems and primary and secondary tillers was not significantly affected by cultivar but was significantly affected by density and year. Averaged across cultivars, densities, and years, main stems and primary and secondary tillers contributed about 15%, 50%, and 35% to total grain yield, respectively. Total grain yield was not significantly related to grain yields of main stems and secondary tillers but was positively and significantly related to grain yield of primary tillers. Approximately 85% of the variation in total grain yield was explained by grain yield of primary tillers, which was positively and significantly related to primary-tiller panicles per m2 but not to spikelets per panicle, spikelet filling percentage, or grain weight of primary tillers. Based on these results, it is concluded that primary-tiller panicle number is essential for achieving high grain yields in machine-transplanted hybrid rice.

Influence of Plant Spacing and Phosphorus Rates on Yield Related Traits and Yield of Faba Bean (Viacia faba L.) in Duna District Hadiya Zone, South Ethiopia

A field experiment was conducted to study the effects of plant spacing and phosphorus rates on yield related traits and yield of faba bean (Viacia faba L.) at Farmers Training Center, Duna District during 2015 summer cropping season. Three intra-rows spacing (5, 10 and 15 cm), three inter-rows spacing (30, 40 and 50 cm) and three phosphorus rates (0, 46 and 92 kg/ha) were tested. The experiment was laid out as a randomized complete block design (RCBD) and was replicated three times. Improved faba bean variety (Degaga) was ued as test crop. Phenological growth parameters yield and yield related data were collected and their ANOVA was analyzed using GenSta 5th edition and while treatment means were significantly different, they were separated using Least Significant Difference (LSD) at 5% probability level. There was highly significant (P<0.01) effect of the highest rate of phosphorus (92 kg P2O5 ha-1) on days to flowering, days to maturity, leaf area index, effective nodules per plant, plant height , primary tillers plant-1, seeds pod-1, hundred seed weight, grain yield, above ground dry biomass and harvest index. Significantly lowest days to flowering (54.3 days) after emergence and highest plant height (105.63 cm), leaf area (1073 cm2), seeds pod-1(3.57), grain yield (2633 kg ha-1), dry biomass (8108kg ha-1) and harvest index (32.47) were obtained from the highest rate of P (92 kg P2O5 ha-1). For all inter-rows spacing, the leaf area, number of primary tillers, pods plant-1, seeds pod-1 and hundred seed weight were increased as intra-row spacing increase and the highest leaf area (1084 cm2), primary tillers (2.99) and hundred seed weight (54.59 g) were obtained from the widest (50 cm) inter-row spacing, while the highest effective nodules (59.56) and leaf area index (3.51) were resulted from the narrowest (30 cm) inter-row spacing. On the other hand, the interaction effects of inter and intra-row spacing significantly influenced, number of pods plant-1, number of seeds pod-1, above ground dry biomass, grain yield and harvest index. The 30 cm inter-row by 15 cm intra-row spacing gave the highest grain yield (2495 kg ha-1), harvest index (35.79%) and pods plant-1(19.68) whereas the highest dry biomass (8738 kg ha-1) was obtained from 30 cm x 5 cm spacing combination. Thus, it can be concluded that application of 92 kg P2O5 ha-1 rate of phosphorus at 30 x 15 cm spacing combination proved to be superior with respect to grain yield in the study area. However, further study at least for one more cropping season under different soils is required to reach at conclusive recommendation.

Correlation analysis of main agronomic traits and contents of diterpene lactones of Andrographis paniculata

In order to study the correlation between the traits of Andrographis paniculata. The main agronomic traits and the content of four kinds of diterpene lactons were measured by the seedlings and the unmutagenized seeds carried by the spacecraft,and multiple comparisons,correlations and principal component analysis were carried out. The results showed that the agronomic traits of A. paniculata have different degrees of difference after being carried by space. The contents of diterpene lactones were quite different. The variation coefficients of deoxyandrographolide content,fresh weight,leaf dry weight,dehydrated andrographolide content,dry weight,neoandrographolide content and andrographolide content were all over 35%. There was a significant correlation between multiple traits,and the leaf weight ratio was significantly positively correlated with the number of primary tillers,leaf dry weight and dry weight,and was significantly negatively correlated with the content of deoxyandrographolide. Andrographolide content was a significantly negatively correlated with the number of leaves and the number of primary tillers,and positively correlated with the other three lactones. Five principal components were extracted from principal component analysis,and the cumulative contribution rate was 83. 127%,which were yield factor,plant type factor,leaf type factor,component factor and seed weight factor. Among the traits affecting the quality of A. paniculata,the yield factor for reliability of the selection of A. paniculata is higher than other factors. There are abundant variations among the traits of A. paniculata,carried in space which increase the genetic diversity. The principal component analysis method can be used to select the principal component factors according to the breeding requirements,which provides a theoretical basis for the breeding of high-yield and high-quality A. paniculata and the high-yield and stable cultivation of A. paniculata.

Yield Response of African Rice Genotypes to Mycorrhizal Fungi and Rhizobium Inoculation

Aims: A short term field study was conducted to investigate the yield performance of selected African rice genotypes inoculated with biofertilizers. 
 Study Design: A randomized complete block design laid out in a split-plot arrangement was used to evaluate response of yield components and grain yield of some selected African rice genotypes will be to mycorrhizal fungi and rhizobium inoculation.
 Place and Duration of Study: The study was conducted at the Teaching and Research farm of the Federal university of technology, Akure Ondo state, Nigeria during the 2013 planting season.
 Methodology: The study was laid out in a split plot arrangement in Randomized Complete Block Design (RCBD), with mycorrhizal fungi, rhizobium inoculation and control in the main plot, while genotypes (N-U-1, N-U-8, WAB 56-104, OFADA GR and MOROBEREKAN) were in the sub-plot and treatments were replicated thrice. There were three main blocks, each block consist of 15 sub-plots with a size measurement of 2m x 1m and inter sub-plot spacing of 0.5m in between plots. A total of 50 plants were raised per sub plot. Transplanted seedlings were planted with the soil slurry containing rhizobium and mycorrhizal fungi inoculum into planting holes in the field at two seedlings per stand, according to their respective plot at a spacing of 25cm x 25cm. Yield component data collected include; number of days to 90% maturity, number of days to 50% flowering; plant height at maturity, number of primary tillers per plot, number of grains per panicle, number of panicles, number of filled and unfilled spikelet, weight of 1000 filled grains and grain yield per plot. 
 Results: Result showed significant (P<0.05) single and interactive effect of rhizobium and mycorrhizal fungi inoculation on rice yield and yield components. 61.4% increase in grain yield was observed in rhizobium inoculated genotypes when compared to 37.4% increase in mycorrhized genotypes and the un-inoculated control. WAB56–104 and N-U-8 had the best interactive response amongst genotypes inoculated with rhizobium while genotypes WAB56-104 and MOROBEREKAN responded better amongst mycorrhized genotypes in relation to yield components.
 Conclusion: The results from this study indicate that African rice genotypes differ in grain yield response and host specifity when inoculated with mycorrhizal fungi and rhizobium inoculums. However, inoculating specific African rice genotypes with mycorrhizal fungi and rhizobium can positively influence their grain yield and yield component development and this could play an important role in improving African rice productivity.

Assessment of phyllochron and tillers contribution to grain yield of rice

Field experiments were carried out at Tamil Nadu Agricultural University, Coimbatore, India during samba (August-December) season of 2012 and 2013 to address the contribution of phyllochron and main culm, primary, secondary and tertiary panicles to grain yield of low land rice with the objective of to investigate the tillering and grain production in main culm, primary, secondary and tertiary tillers due to varied crop geometry, age and number of seedlings in rice. The experiment consisted of three main-plot treatments and replicated thrice in a split plot design. Crop geometry of 25 x 25 cm in association with 14 DOS with one seedling hill −1 resulted higher panicle weight (5.35, 4.16, 3.55 and 2.90 g) on main culm, primary, secondary and tertiary panicles, respectively compared to all other combinations. Combination of transplanting of rice at wider spacing of 25 x 25 cm and 14 DOS with one seedling hill−1 was found to record higher grain yield (7303 kg ha −1) than other treatments.