Water deficits cause major yield reductions on the world’s rainfed riceland. The most severe water deficits occur during the reproductive phase. Differences in canopy temperature among crop cultivars are known to be related to drought avoidance characters. In developing a practical field screening system for reproductive phase drought resistance in rice (Oryza sativa L.), we assessed the canopy temperature response of a range of germplasm, and related the results to other plant characters related to drought resistance. Field experiments were conducted on a silty clay loam Typic Hapludoll at the International Rice Research Institute. Planting of the test cultivars was staggered, to synchronize flowering during the water-deficit period. Canopy temperature measurements were made on 12 dates in Trial 1 and 8 dates in Trial 2. Mean canopy temperatures (Tc) increased from 28 to 37 degrees C during the stress period. Grain yield (r2 = -0.63**) and spikelet fertility (r2 = 051**) were related to midday Tc on the day of flowering. Highly significant differences were observed in canopy temperature among entries, with low coefficients of variation (2.0-2.7%). Entries with a history of outstanding vegetative stage drought screening scores consistently remained coolest under stress. Visual drought tolerance scores (r = 0.72**) and leaf rolling scores (r = 0.68**) were correlated with mean canopy temperatures under moderate water stress, but not under severe stress (r =
Tag: growth rate
Effect of growing medium on early growth and survival of Uaparka kirkiana Môell Arg. seedlings in Malawi
The use of appropriate growing medium has been an important factor influencing growth and survival of seedlings in the nursery. Raising Uapaca kirkiana rootstocks from seeds has been a challenge as pencil-size stem thickness is required before grafting can be done. An experiment was carried out with the objective of determining an effective growing medium that ensures survival and rapid growth of U. kirkiana seedlings. Ten different combinations of sand, forest soil and sawdust amended with four different levels of nitrogen, phosphorus and potash fertilizer were evaluated. The result showed that the growing medium comprising 75% forest soil and 25% sawdust produced the tallest seedlings with larger root collar diameter and higher survival at ten months after planting. Amending the same growing medium with fertilizer improved the root collar diameter of the seedlings. It is concluded that a growing medium comprising 75% forest soil and 25% sawdust and amended with NPK fertilizer was superior in improving U. kirkiana seedling growth to attain a suitable diameter for grafting within ten months.
Survival and Growth Performance of Calophyllum inophyllum L. Seedlings in Peat Soil and at Different Levels of Groundwater
Selecting proper tree species for revegetation is important for restoring tropical peatland. Tamanu (Calophyllum inophyllum L.) has been suggested one of the promising native species in Indonesia for the revegetation of tropical peatland; however, there is a lack of understanding of its growth in peat soil with different groundwater levels. We investigated the survival rate, plant height, number of leaves, root collar diameter, and dry biomass of tamanu seedlings grown in peat soil with different groundwater levels using a randomized block design in a water tank. The study involved five groundwater level treatments and 12 tree-level replicates each: M0 (non-groundwater level, control); M1 (−15 cm below the soil surface); M2 (−10 cm); M3 (−5 cm); and M4 (0 cm, soil surface level). The results showed that all tamanu seedlings survived in every treatment. However, their plant height, number of leaves, and root collar diameter growth were significantly inhibited in the highest groundwater level condition (M4, 0 cm) at 81 days after sowing, while their growth in −15 cm of groundwater level (M1) was as good as the growth in the fully drained conditions in M0 (control). This result indicates that the groundwater level should not be higher than −15 cm for the growth of tamanu. Considering that peatlands in Indonesia are assessed to be degraded when the groundwater level is lower than −40 cm, this study suggests that maintaining groundwater levels between −40 cm and −15 cm in peatland is the best condition for rapid growth of early tamanu seedlings while protecting peatlands. Further studies are needed to extend the range of water levels and water treatment duration.
Earlier onset and slower heartwood investment in faster-growing trees of African tropical species
Heartwood plays an important role in maintaining the structural integrity of trees. Although its formation has long been thought to be driven solely by internal ageing processes, more recent hypotheses suggest that heartwood formation acts as a regulator of the tree water balance by modulating the quantity of sapwood. Testing both hypotheses would shed light on the potential ecophysiological nature of heartwood formation, a very common process in trees. We measured quantities of heartwood and sapwood, xylem conduits and the width and number of growth rings on 406 stems of Pericopsis elata with ages ranging from 2 to 237 years. A subset of 17 trees with similar ages but varying growth rate were sampled in a shaded (slower-growth) site and a sun-exposed (faster-growth) site. We used regression analysis and structural equation modelling to investigate the dynamics and drivers of heartwood formation. We found a positive effect of growth rate on the probability of heartwood occurrence, suggesting an earlier heartwood onset in faster-growing stems. After this onset age, heartwood area increased with stem diameter and age. Despite the similar heartwood production per unit stem diameter increment, shaded trees produced heartwood faster than sun-exposed trees. Tree age and hydraulics showed similar direct effects on heartwood and sapwood area of sun-exposed trees, suggesting their mutual role in driving the heartwood dynamics of sun-exposed trees. However, for shaded trees, only tree hydraulics showed a direct effect, suggesting its prominent role over age in driving the heartwood dynamics in limited growing conditions. The positive relationship between growth rate and maximum stomatal conductance supported this conclusion. Heartwood area increases as the tree ages, but at a slower rate in trees where water demand is balanced by a sufficient water supply. Our findings suggest that heartwood formation is not only a structural process but also functional.
Growth and biomass production of five exotic bamboo species in North-western Ethiopia
Forests provide goods and services and the demand for these has increased over the years. To meet this demand, reforestation using fast-growing species is crucial. Bamboo is amongst the fastest-growing plant species. Consequently, the Ministry of Agriculture/East Africa Bamboo Project and the European Union Energy Project/INBAR introduced twenty-three bamboo species to Ethiopia. This study assessed the growth and biomass production potential of five of these exotic bamboo species (Dendrocalamus membranaceus, Dendrocalamus asper, Dendrocalamus hamiltonii, Bambusa vulgaris and Guadua amplexifolia). A randomized complete block design (RCBD) with three replications was used. Nine seedlings of each species were planted per plot using two meters spacing between and within rows. Sprouted culms per clump, culm length, culm diameter at breast height (DBH), average number of nodes and internode length per culm were measured. At age of 3½ years after planting, one clump of each species per plot in each block was uprooted and sorted into different components (rhizome, culm, branch and leaves). The fresh weight of each component was measured and sub-samples were taken to dry to constant weight. One-way ANOVA and then Tukey’s test were used to find significantly different group means. The growth performance, in terms of culm production, culm height, internode length and biomass production, of the species was significantly different. D. asper and D. hamiltonii had superior growth and biomass production. We therefore recommend planting these two species in Guangua district and other similar areas where they can enhance the livelihoods of the communities.
Growth and profitability performance of three accessions grafts and seedlings of Tamarindus indica (Fabaceae) planted in the Groundnut Basin of Senegal
Tamarindus indica is a priority local forest food tree in the Sahel. It is an important source of income for many rural families. It is still in the wild, apart from a few specimens of the accessions recently introduced into the landscape of Sahelian villages. The objective of the present study is to investigate the performance and efficiency of three accession grafts and the effect of grafting to shorten the juvenal growth and fruiting periods for improving woody species diversity in agroforestry parklands and diversifying the sources of income of small producers. The design was a randomized complete block with 5 replications. Each block was composed of 5 grafts of three accessions (Niger 309, TB3, Sweet Thailand) and 5 seedlings propagated from wild tree seeds. Growth parameters (height, collar diameter, canopy width and primary branch number) were measured on all plants. The evaluation of fruiting potential was made on 5 plants of each accession in the first year and 10 plants in the second year. Cost–benefit analysis were carried out to assess the financial viability and economic profitability of planting these accessions of T. indica. The results show that Sweet Thailand accession had the best growth performance compared to Niger 309 and TB3. Fruiting of the three accession grafts started in the second year after planting, in contrast to seedlings which started to bear fruit from the fourth year. TB3 grafts had higher average fruit production in 2017 and 2018 (120 and 640 kg ha−1, respectively). The cost–benefit analysis shows that planting of the three accession grafts is financially viable and economically profitable. The results of the present study indicated that planting these three accessions might play an important role in food security, the resilience of small-scale farmers and the improvement of biodiversity in the landscape.
Supplementation with Schizochytrium sp. enhances growth performance and antioxidant capability of dairy calves before weaning
This study aimed to determine the effect of microalgae (Schizochytrium sp., SZ) supplementation on the growth performance, rumen fermentation parameters, and antioxidant capacity of dairy calves. Fifty newborn female Holstein calves (1 d old, 39.8 ± 0.77 kg initial body weight) were randomly assigned to 1 of 5 groups (n = 10). The 5 groups of calves were fed with whole milk (d 4 to d 22) or milk replacer (d 23 to d 60) supplemented with (per calf per d) 0 g (control, SZ0), 5 g (SZ5,0.55 g/d DHA), 10 g (SZ10, 1.11 g/d DHA), 20 g (SZ20, 2.22 g/d DHA), or 40 g (SZ40, 4.44 g/d DHA) of SZ powder from day 4 to day 60. The daily supplementations of SZ were equally divided and offered twice daily (via milk pail) at 0800 and 1500 h. During the experiment, dry matter intake of whole milk/milk replacer and starter and fecal score were recorded daily, while bodyweight (BW) was measured biweekly at days 1, 14, 28, 42, and 60, and withers height was measured at days 1 and 60. Blood was sampled after the afternoon feeding from the jugular vein at days 28 and 60 for serum antioxidant capacity detection (malondialdehyde, glutathione peroxidase, catalase and superoxide dismutase). Rumen fluid was sampled after the morning feeding via a flexible esophageal tube at days 14, 28, 42 and 60 for pH, ammonia nitrogen and volatile fatty acids measurements. The final BW and average daily gain (ADG) increased quadratically as SZ increased (P < 0.05), and SZ20 group of ADG was numerically higher than other groups. Feed:gain (F:G) ratio decreased quadratically as SZ increased (P < 0.05), and SZ20 group was numerically lower than other groups. Withers height tended to increase linearly as SZ increased (P < 0.1). The concentration of propionate tended to decrease linearly as SZ increased in rumen fluid (P < 0.1). Malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and catalase (CAT) increased linearly as SZ increased in blood (P < 0.05). Taken together, this study demonstrated the positive effects of SZ supplementation on growth performance and antioxidant capacity of calves. At the same time, SZ supplementation tended to reduce the concentration of rumen propionate, particularly in high dosage SZ group. Considering the above, the optimal amount of SZ supplementation for dairy calves suggested by the present study is 20 g/d. © 2020 Elsevier B.V.
The growth performance of dipterocarps species and understorey diversity in the Gunung Dahu Research Forest, Leuwiliang, Bogor
Dipterocarps species is the main species composes Gunung Dahu research forest. Habitat suitability and growth performance of a species are some factors considered in the species selection for forest establishment. The understorey in a forest community serves to protect soil from erosion. This research aimed is to analyze the growth performance of various Dipterocarpaceae species and study understorey diversity in the research area. The measurement was conducted in four species trial plots contain ten Dipterocarps species consist of five individuals per species per plot or 200 individuals in total. The growth performance of Dipterocarp species was analyzed using the current annual increment (CAI) and mean annual increment (MAI) methods. The understorey diversity was analyzed using the Shannon-Wiener Index. The result showed that Shorea johorensis obtained the highest CAI, 0.95 cm year-1, and Shorea platyclados got the highest MAI, 1.78 cm/year. S. platyclados and S. leprosula were projected to reach <40 cm in diameter after they got 25 years. The Gunung Dahu research forest's understorey was classified as moderate (1.68-2.33). The dominant understorey species, namely Oldenlandia auricularia, Neprolephis biserrate, Ottochloa nodosa, and Gleichenia linearis. This study concluded that the growth performance of Dipterocarps species in the study area varied, and the understorey condition was classified as moderate, where its diversity has a positive correlation with the crown openness. © Published under licence by IOP Publishing Ltd.
Habitat Quality Differentiation and Consequences for Ecosystem Service Provision of an Amazonian Hyperdominant Tree Species
Ecosystem services of Amazonian forests are disproportionally produced by a limited set of hyperdominant tree species. Yet the spatial variation in the delivery of ecosystem services by individual hyperdominant species across their distribution ranges and corresponding environmental gradients is poorly understood. Here, we use the concept of habitat quality to unravel the effect of environmental gradients on seed production and aboveground biomass (AGB) of the Brazil nut, one of Amazonia’s largest and most long-lived hyperdominants. We find that a range of climate and soil gradients create trade-offs between density and fitness of Brazil nut trees. Density responses to environmental gradients were in line with predictions under the Janzen–Connell and Herms–Mattson hypotheses, whereas tree fitness responses were in line with resource requirements of trees over their life cycle. These trade-offs resulted in divergent responses in area-based seed production and AGB. While seed production and AGB of individual trees (i.e., fitness) responded similarly to most environmental gradients, they showed opposite tendencies to tree density for almost half of the gradients. However, for gradients creating opposite fitness-density responses, area-based seed production was invariable, while trends in area-based AGB tended to mirror the response of tree density. We conclude that while the relation between environmental gradients and tree density is generally indicative of the response of AGB accumulation in a given area of forest, this is not necessarily the case for fruit production.
Supplementation with sodium butyrate improves growth and antioxidant function in dairy calves before weaning
Background: There is increasing research interest in using short-chain fatty acids (SCFAs) including butyrate as potential alternatives to antibiotic growth promoters in animal production. This study was conducted to evaluate the effects of supplementation of sodium butyrate (SB) in liquid feeds (milk, milk replacer, and the mixture of both) on the growth performance, rumen fermentation, and serum antioxidant capacity and immunoglobins in dairy calves before weaning. Forty healthy female Holstein calves (4-day-old, 40 ± 5 kg of body weight) were housed in individual hutches and randomly allocated to 1 of 4 treatment groups (n = 10 per group) using the RAND function in Excel. The control group was fed no SB (SB0), while the other three groups were supplemented with 15 (SB15), 30 (SB30), or 45 (SB45) g/d of SB mixed into liquid feeds offered. The calves were initially fed milk only (days 2 to 20), then a mixture of milk and milk replacer (days 21 to 23), and finally milk replacer only (days 24 to 60). Results: The SB supplementation enhanced growth and improved feed conversion into body weight gain compared with the SB0 group, and the average daily gain increased quadratically with increasing SB supplementation. No significant effect on rumen pH; concentrations of NH3-N, individual and total VFAs; or acetate: propionate (A:P) ratio was found during the whole experimental period. Serum glutathione peroxidase activity increased linearly with the increased SB supplementation, while the serum concentration of maleic dialdehyde linearly decreased. Serum concentrations of immunoglobulin A, immunoglobulin G, or immunoglobulin M were not affected by the SB supplementation during the whole experimental period. Conclusions: Under the conditions of this study, SB supplementation improved growth performance and antioxidant function in pre-weaned dairy calves. We recommended 45 g/d as the optimal level of SB supplementation mixed into liquid feeds (milk or milk replacer) to improve the growth and antioxidant function of dairy calves before weaning. © 2021, The Author(s).