Effects of temperature pre-treatment of transplants from in vitro produced potato plantlets on transplant growth and yield in the field

Summary In vitro produced potato plantlets, cvs Gloria and Spunta were planted in soil and exposed to day/night temperatures of 18/12 or 26/20°C for 14 days. They were then transplanted into the field in two experiments to assess after-effects of temperature on the performance of short-cycle crops. Accumulated intercepted radiation (AIR) was calculated from ground cover and incoming radiation, and dry matter production and fresh tuber yield were frequently recorded. Pre-treatment at 26/20°C caused higher leaf area at the end of the transplant production phase and resulted in a higher AIR at the end of the field phase than pre-treatment at 18/12°C. Higher AIR, however, was not associated with significantly higher yield. Initially, the proportion of dry matter partitioned to tubers was lower after 26/20°C, but this effect did not persist. High temperature pre-treatment may improve the performance of plantlets, especially of very early potato cultivars.     

Potato production from true potato seed (TPS) in Egypt: Effect of the growing season on seedling development,recovery from transplanting and yield

Summary Ware potatoes were produced from true potato seed by transplanting seedlings to the field in different growing periods to evaluate environmental constraints of this production method in the Nile delta. In the autumn season, with high temperatures and long-day conditions during seedling culture in the nursery and transplant establishment in the field, seedling development was fast, and transplants resumed growth within 5 days of transplanting in the field. Tuber yields ranged between 120 and 160 dt ha⁻¹. In the spring season, with low temperatures and short-day conditions during the initial growing phase, seedling development in the nursery was slow and biomass partitioning between above ground organs (stems, leaves) and tubers was shifted towards the tubers. This partitioning was further enhanced by transplanting the seedlings in the field. Seedlings recovered only slowly from transplanting or died. It is concluded that potato production via transplants is poor in the spring season when premature tuberization of seedlings in the nursery leads to slow field establishment and low tuber yield.     

Field performance of potato microtubers as propagation material

Summary In five field trials with the cultivars Gloria (early), Bintje (mid-early) Désirée (mid-late) and Morene (late), crops grown from conventional 28–35 or 35–45 mm seed were compared with crops grown from microtubers, of various sizes and from various sources, that had been producedin vitro. The following means to quicken initial crop development from the micropropagated material were tested: large microtubers, plastic soil cover, and transplanting of plantlets grown from microtubers pre-planted in a glasshouse. Crops grown from microtubers weighing less than half a gram yielded much less than crops grown from conventional seed crops but their yields were increased by each treatment. With the later-maturing cultivars, which generally produce few tubers per plant, the yields within seed grades from plants grown from transplanted microtuber plants were comparable with those of conventional crops. Reasons are given, why direct planting of microtubers, with or without plastic foil, is not a practical option.     

The response of cassava (Manihot esculenta) to spatial arrangement and to soybean intercrop

Response of cassava to row spacing and plant population density (0.62 plants m⁻² in 180-cm rows; 1.23 plants m⁻² in 90-, 180-, 270-, and 270- plus 90-cm (i.e. paired rows); and 2.46 plants m⁻² in 90- and 180-cm rows), and to soybean intercrop at two row spacings of cassava (90 and 270 cm) was studied at a high latitude (27°S) in south-east Queensland, Australia, where low temperature limits a growing season to 9 months. Detailed observations were made in sole crops on leaf canopy structure and light penetration in the three row spacings at the medium density to allow an estimation of light availability for an intercrop between cassava rows.The low plant density or the 270-cm row plants produced the lowest total dry matter and tuber yield at harvest, while the two higher densities or the two narrower rows produced similar total and tuber dry weight. Intercropped cassava produced a similar tuber yield to the sole crop at the corresponding spatial arrangement, but total dry matter was lower in the former.Leaf area index was similar among the 90-, 180- and 270-cm row spacings in sole crops throughout the growth period. However, leaf area was unevenly distributed horizontally for a longer time as row spacing increased. This resulted in light penetrating the inter-row space for a longer period in wider rows in sole crops, more than 50% full sunlight reaching soil level for 90, 120 and 130 days after planting in the 90-, 180- and 270-cm rows, respectively. This light environment would be available for an intercrop if cassava growth is not affected by the intercrop. The results for cassava intercropped with soybean show that in fact cassava growth was reduced by the associated soybean, and hence light available for the soybean growth would have been more than that estimated above.     

Estimating theoretical radiation‐use efficiency for kale crops

Establishing the radiation‐use efficiency (RUE) of forage brassica crops will aid our understanding of their photosynthetic performance. The concept of RUE has been developed for cereals and legumes, but there is limited information for forage brassica crops. Three experiments defining the influence of different sowing dates on ‘Gruner’ kale (Brassica oleracea acephala L.) dry matter production were conducted at Hastings (Hawkes Bay) and Lincoln (Canterbury) in New Zealand between 2002 and 2009. These trials were also evaluated for radiation interception and RUE. Delayed sowing increased RUE in two out of three experiments across sites: from 1·93 g MJ^?1 photosynthetically active radiation (PAR) for December‐sown crops to 2·72 g MJ^?1 PAR (P < 0·001) for January‐sown crops at Hastings and from 1·50 for September‐sown crops to 2·00 g MJ^?1 PAR (P < 0·001) for November‐sown crops at Lincoln. The different sowing dates and years of experimentation provided a range of mean temperatures (from 13 to 16°C) during the vegetative period. Across years and sowing dates, RUE was strongly correlated with mean temperature (R² = 0·81) and sowing date (R² = 0·64), but weakly correlated with season length (R² = 0·11) and dry matter (R² = 0·002). There was also a strong correlation (R² = 0·83) between sowing date and mean temperature. The increase in RUE with delayed sowing was therefore mainly attributed to increased mean temperatures. Radiation‐use efficiency increased at about 0·41 g MJ^?1 for each 1°C increase from 13 to 16°C.     

Growth and yield of perennial cassava in the subhumid subtropics

Growth and tuber yield of perennial cassava crops of up to 4 years' duration were compared with those of annual crops in a subhumid subtropical environment where low winter temperature limits crop growth to 8–9 months per year.Resumption of growth by perennial cassava was rapid; sprouting occurred at many nodes in spring, and its canopy intercepted more solar radiation than did young annual crops. However, total biomass production during a season was generally slightly less than that of annual crops.After four seasons of cropping, four annual crops combined produced 49.4 t ha⁻¹ of tuber dry weight. Corresponding yields for two 2-year crops, one annual plus one 3-year crop, and one 4-year crop, were 44.7, 40.3 and 38.1 t ha⁻¹, respectively. The higher productivity of the annual crops was partly related to irrigation applied in the first three seasons to the annual crops. In the fourth season when no irrigation was applied to any crop, the annual increments of tuber weight in 2- and 4-year crops were similar to the tuer yield of the annual crop. It was concluded that productivity of a 2-year crop is 90–100%, and that of 3- and 4-year crops is 80–90%, that of annual cassava.     

The feasibility of predicting the number of stems per tuber produced by potato seed stocks from measurements made before planting

Summary The number of stems per seed tuber produced by 17 seed stocks of cv. Record was determined in glasshouse and field experiments to assess the feasibility of predicting the number of stems produced in the field. Multiple regression analysis showed that seed tuber weight alone gave the most satisfactory fit to stems produced in the field, which was not improved by adding terms involving the number of stems produced in the glasshouse. Quadratic relationships between the number of above-ground stems per tuber and tuber weight were most appropriate for each stock, with the fitted curves for individual stocks differing only in the constant term. However, there were significant rank correlation coefficients between the constant terms for relationships between field stems and tuber weight and glasshouse stems and tuber weight, suggesting that in other cultivars and seed stocks a predictive glasshouse test might still be useful.     

Performance of true potato seed families. 2. Comparison of transplants vs. seedling tubers

Summary A potato crop can be grown from true potato seed (TPS) either by transplanting seedlings to the field (seedling transplants) or by planting tubers derived from seedlings (seedling tubers). The effect of the planting method on performance of TPS families was evaluated for three types of families, 4x×2x hybrid, open pollinated, and self pollinated. Families from seedling transplants and seedling tubers and their 4x parental clones were compared for tuber yield and specific gravity. Families from tubers had substantially higher yields and significantly more uniform specific gravity than families from transplants. Hybrid seedling tuber families had a higher mean yield than the parental clones and did not differ from them in specific gravity. Selection in the seedling generation could further improve both OP and hybrid families from transplants and from seedling tubers. Paper no. 3163 from the Department of Genetics, University of Madison.     

The response of autumn and spring sown sugar beet (Beta vulgaris L.) to irrigation in Southern Italy: Water and radiation use efficiency

The Apulia region in Southern Italy is an important area for sugar beet cultivation. It is characterised by clay soils and a hot-arid and winter-temperate climate. The capability of sugar beet to exploit solar radiation, water use and irrigation supply in root yield, total dry matter and sucrose production was studied and analysed in relation to two experimental factors: sowing date – autumn (October–December) and spring (March) – and irrigation regime – optimal and reduced (respectively with 100 and 60% of actual evapotranspiration). Data sets from three experiments of spring sowing and three of autumn sowing were used to calculate: (1) water use efficiency in the conversion in dry matter (WUE_dm, plant dry matter at harvest versus seasonal water use ratio), in sucrose (WUE_suc, sucrose yield versus seasonal water use ratio); (2) irrigation water use efficiency in the conversion in dry matter (IRRWUE_dm), in sucrose (IRRWUE_suc) and fresh root yield (IRRWUE_fr); and (3) radiation use efficiency (RUE, plant dry matter during the crop cycle and at harvest versus intercepted solar radiation ratio).Autumnal beet was more productive than spring for fresh root, plant total dry matter, sucrose yield and concentration; also WUE_suc and IRRWUE_s were higher in the autumnal sugar beet, but no difference was observed in WUE_dm (on average, 2.83 g of dry matter kg⁻¹ of water used). An average saving of about 26% of seasonal irrigation supply (equivalent to about 100 mm) was measured in the three years with the earliest sowing time. The optimal irrigation regime produced higher root yield, plant total dry matter and sucrose yield than the reduced one; on the contrary the IRRWUE_fr and IRRWUE_dm were higher in the reduced irrigation strategy. WUE_s and IRRUWE_s correlated positively with the length of crop cycle, expressed in growth degree days and, in particular, to the length of the period from full soil cover canopy to crop harvest, the period when plant photosynthetic activity and sucrose accumulation are at maximum rates. Seasonal RUE was higher in the spring than in the autumn sowing (1.14 μg J⁻¹ versus 1.00 μg J⁻¹). The RUE values during the crop cycle reached the maximum in the period around complete canopy soil cover. The results showed the importance for better use of water and radiation resources of autumnal sowing time and of reduced irrigation regime in sugar beet cropped in a Mediterranean environment.     

Salinity reduces radiation absorption and use efficiency in soybean

The potential rate of plant development and biomass accumulation under conditions free of environmental stress depends on the amount of radiation absorption and the efficiency of utilizing the absorbed solar energy to drive photosynthetic processes that produce biomass materials. Salinity, as a form of soil and water stress, generally has a detrimental effect on plant growth, and crops such as soybean are usually sensitive to salinity. Field and greenhouse experiments were conducted to determine soybean growth characteristics and the relative impact of salinity on radiation absorption and radiation-use efficiency (RUE) at a whole plant level. Cumulative absorption of photosynthetically active radiation (∑APAR) was estimated using hourly inputs of predicted canopy extinction coefficients and measured leaf area indices (LAI) and global solar radiation. On 110 days after planting, soybean plants grown under non-saline conditions in the field accumulated 583 MJ ∑APAR m⁻². A 20% reduction in ∑APAR resulted from growing the plants in soil with a solution electrical conductivity (EC) of about 10 dS m⁻¹. Soybeans grown under non-saline conditions in the field achieved a RUE of 1.89 g MJ⁻¹ ∑APAR for above-ground biomass dry materials. The RUE reached only 1.08 g MJ⁻¹ ∑APAR in the saline soil, about a 40% reduction from the non-saline control. Salinity also significantly reduced ∑APAR and RUE for soybeans in the greenhouse. The observed smaller plant and leaf sizes and darker green leaves under salinity stress were attributed to reductions in LAI and increases in unit leaf chlorophyll, respectively. Reductions in LAI exceeded small gains in leaf chlorophyll, which resulted in less total canopy chlorophyll per unit ground area. Analyzing salinity effect on plant growth and biomass production using the relative importance of ∑APAR and RUE is potentially useful because APAR and total canopy chlorophyll can be estimated with remote sensing techniques.     

江苏淮北地区不同栽培方式对水稻产量和物质生产特征的影响

以大穗、特早熟籼粳品种甬优2640为材料,对钵苗机栽、旱育手栽和毯苗机插3种栽培方式水稻的产量、干物质积累、茎蘖动态等进行比较研究。结果表明,3种不同栽培方式间水稻产量存在显著差异,钵苗机栽、旱育手栽产量极显著高于毯苗机插,钵苗机栽显著高于人工手栽,产量差异主要来源于每穗粒数;物质生产上,移栽至N-n叶龄期钵苗机栽和旱育手栽物质积累量多于毯苗机插,无效分蘖期毯苗机插物质积累量较多,至拔节期不同栽培方式干物质量相当,拔节至抽穗期、抽穗至成熟期钵苗机栽旱育手栽毯苗机插,三者间存在显著差异。说明与毯苗机插、旱育手栽相比,钵苗机栽水稻全生育期干物质积累(除无效分蘖期)都具有一定优势,特别是生育中、后期物质积累多,叶片不早衰,结实率和千粒重较高。     

Effect of daminozide on survival,growth and yield of micropropagated potatoes

The effect of daminozide [Butanedioic acid mono (2,2-dimethyl hydrazide)] on growth, field establishment and productivity of micropropagated Kennebec and Russet Burbank potato was studied. Addition of daminozide to the medium significantly reduced stem length ofin vitro propagated plantlets. Optimal dose was 0.6 mg active ingredient per plant. This dose did not significantly alter the number of nodes and leaf area. Three transplanting methods were examined: direct from tissue culture to the field without protection; the same but with a plastic covering for protection; and after 7 days acclimation in a greenhouse but without protection in the field. Stand establishment ranged from 83.3 to 100%. The second transplanting method had the highest percentage establishment for both cultivars. The application of daminozide improved survival for all transplants of Kennebec and the directly planted plantlets of Russet Burbank. Independent of the daminozide treatment, plants of both cultivars hardened in the greenhouse prior to transplanting produced the highest number and yield of tubers. For Russet Burbank, daminozide caused a delay in tuberization but did not affect tuber bulking and haulm growth.     

Diplazium sammatii: Athyraceae (`Nyama Idim'): Age-related nutritional and antinutritional analysis

Tender and mature leaflets and leaves of Diplazium sammatii (`Nyama idim'), were separately investigated for their nutritional and antinutritional properties. Results showed little difference in proximate nutritional contents between tender and mature leaves, except for crude fat, which was present in levels 1.5 times higher in younger than in older leaves. Crude fiber levels were low. Zinc (Zn) and copper (Cu) were higher in younger leaves (6.8 and 3.5 mg/100 g dry matter, respectively, compared to 4.5 and 2.5 mg/100 g dry matter, respectively in older leaves). Older leaves contained higher levels of iron (Fe): 6.7 mg/100 g dry matter, in comparison to 4.3mg/100 g dry matter, in young leaves. Oxalate levels were slightly higher in younger than older leaves. However, the reverse was true for tannin content. Both antinutritional compounds were present in levels which shouldbe safe.     

Effect of nitrogen supply on crop conductance,water- and radiation-use efficiency of wheat

Water-use efficiency (WUE_DM) is directly related to radiation-use efficiency (RUE) and inversely related to crop conductance (g_c). We propose that reduced WUE_DM caused by shortage of nitrogen results from a reduction in RUE proportionally greater than the fall in conductance. This hypothesis was tested in irrigated wheat crops grown with contrasting nitrogen supply; treatments were 0, 80 and 120 kg N ha⁻¹ in 1998 and 0, 80, 120 and 160 kg N ha⁻¹ in 1999. We measured shoot dry matter, yield, intercepted solar radiation and soil water balance components. From these measurements, we derived actual evapotranspiration (ET), soil evaporation and transpiration, WUE_DM (slope of the regression between dry matter and ET), WUE_Y (ratio between grain yield and ET), RUE (slope of the regression between dry matter and intercepted radiation), and g_c (slope of the regression between transpiration and intercepted radiation). Yield increased from 2.3 in unfertilised to an average 4.7 t ha⁻¹ in fertilised crops, seasonal ET from 311 to 387 mm, WUE_DM from 23 to 37 kg ha⁻¹ mm⁻¹, WUE_Y from 7.6 to 12.4 kg ha⁻¹ mm⁻¹, RUE from 0.85 to 1.07 g MJ⁻¹, while the fraction of ET accounted for soil evaporation decreased from 0.20 to 0.11. In agreement with our hypothesis, RUE accounted for 60% of the variation in WUE_DM, whereas crop conductance was largely unaffected by nitrogen supply. A greater fraction of evapotranspiration lost as soil evaporation also contributed to the lower WUE_DM of unfertilised crops.     

A high seed yield and associated attributes of dry matter production achieved by recent Japanese soybean cultivars

Field experiments were carried out in 2014 and 2015 to characterize the associated attributes responsible for dry matter accumulation in high-yielding soybean. We attempted to create a high-yielding environment by introducing narrow-row planting at two planting densities, using a new cultivar ‘Hatsusayaka’ and a current leading cultivar ‘Sachiyutaka’ in an upland experimental field. Dry matter accumulation was assessed in terms of light interception and radiation use efficiency (RUE). Growth analysis was performed to evaluate the crop growth rate (CGR) and the contribution of the net assimilation rate (NAR) and mean leaf area index to CGR. Maximum soybean yields of 590 and 658 g m^?2 were obtained for Hatsusayaka and Sachiyutaka, respectively, in 2015 at the high planting density, with the corresponding maximum aboveground dry matter equaling 1463 and 1331 g m^?2 and maximum LAI equaling 8.5 and 7.6. Although cumulative intercepted solar radiation was lower than in previous studies, early canopy closure at around the beginning of the flowering stage and very high RUE (1.54 and 1.68 g MJ^?2 for Hatsusayaka and Sachiyutaka, respectively) contributed to the high dry matter accumulation. In contrast to the high yield in 2015, continuous excess soil moisture in early August 2014 may have inhibited nodule nitrogen fixation and decreased the nitrogen content, resulting in an extremely high specific leaf area and low leaf greenness, which agrees well with the low NAR during the corresponding period.     

Comparison of the growth of potato crops grown in autumn and spring in North Africa

Summary The relationships between intercepted solar radiation and dry matter production (total and tubers) were established for four cultivars of different maturity classes and using seed tubers of two physiological ages. The crops were grown in an autumn and a spring season in Tunisia. Radiation use efficiencies were lower in autumn than in spring and the quantity of intercepted radiation at tuber initiation was more than two times greater in autumn than in spring due to retarded tuberization in the autumn caused by the relatively high temperatures. In addition, tuber dry matter, number of stems per plant, tubers per stem and harvest indices were all lower in the autumn than in the spring season which explained why tuber yields in the spring season were higher than in the autumn.     

Growth in Netted Gem potatoes as influenced by transplanting and by greensprouting

The basis of difference in field growth and yield in Netted Gem potato plants grown from greenhouse transplants, from seed which was greensprouted for two weeks prior to planting and from seed which was retained in storage until planting was studied by measuring changes in plant dry weight and leaf area throughout the season. Cut seed, approximately 70g in size, which were either two or four-cut from 142g or 283g mother tubers respectively, were used in the comparisons. Transplants were started in 7.6 cm peat pots in the greenhouse and were transplanted to the field when 10 cm high. The greensprouted seed was cut from mother tubers which had been sprouted under fluorescent light at 15–18°C for two weeks producing strong sprouts 5 mm long. Transplants, greensprouted seed and seed from mother tubers held in 3°C storage were all planted in the field May 30, 1974, coinciding with commercial plantings of Netted Gem in the province. Backup field experiments, comparing similarly treated greensprouted and storage seed and transplants, were conducted in 1974 and 1975 but were not subjected to growth analysis. All plantings were grown on a Riverbank sandy loam soil. The 1974 growing season in New Brunswick was excellent while that for 1975 was dry and required extensive irrigation. The use of transplants established a substantial advantage in terms of early emergence and yields were consistently and significantly greater than those of greensprouted-seed and unsprouted-seed plants. The transplant yield advantage was attributed to the fact that tuberization was advanced substantially compared with the latter two types. Higher relative growth rates were associated with later emergence so that the rate for plants growing from unsprouted seed was greater than that for plants growing from greensprouted plants which, in turn, was superior to that of transplants. This pattern was maintained through the season. Consequently, small advantages in time of emergence, such as that obtained with greensprouted-seed plants, were not accompanied by significant yield differences. Canopy size decreased as emergence was delayed and canopy size differences were determined largely by the amount of branching. As canopy size decreased and emergence was delayed, the net assimilation rate was found to increase.     

种植密度和施氮水平对华南8号木薯产量形成的影响

在不同种植密度和施氮水平条件下探讨华南8号木薯干物质积累、分配的规律及其对产量形成的影响。结果表明,低密度低施氮水平处理的产量显著高于高密度高施氮水平处理;低密度低施氮水平处理的单条薯重显著高于高密度高施氮水平处理,并且交互作用显著;低密度和低施氮水平处理虽然前期干物质生产速率较低,但后期干物质生产速率及其向块根的分配比例明显高于高密度和高施氮水平。     

木薯和花生间作模式下2种作物光合与干物质积累特性

为研究木薯和花生间作模式下2种作物光合与干物质积累特性,以木薯和花生间作行数比为2∶4模式为对象,木薯单作（SC）、花生单作（SP）为对照,在大田条件下测定了该间作系统中2种作物（木薯用IC表示,花生用IP表示）不同时期干物质积累特点和光合特性。结果表明：（1）花生实际产量和预期产量均表现出先增后降的趋势,且在定植后92 d之前的实际产量大于预期产量,之后的实际产量和预期产量均开始下降;木薯实际产量从定植后75 d到收获均大于预期产量,且实际产量的增加速度大于预期产量的增加速度。（2）块根形成期和块根膨大期,IC植株叶片的最大净光合速度（P_nmax）和光饱和点（LSP）均显著高于SC;苗期和块根膨大期,IC植株叶片的暗呼吸速度（R_d）小于SC。荚果膨大期,IP植株叶片的光补偿点（LCP）、LSP和R_d均显著低于SP,表观量子效率（α）显著高于SP。（3）IC通过最大干物质积累速率出现时间提前、延长快增期持续天数和提高最大干物质积累速率来达到增加干物质理论最大积累量;IP通过提早快增期开始时间和快增期结束时间来缩短快增期持续天数,并使其最大干物质积累速率出现时间提前,最终使IP的干物质理论最大积累量下降。综上表明,木薯通过提高光能截获和利用效率,同时降低自身消耗来增加干物质积累量,花生后期由于高位作物的遮荫影响其生长发育,但在荚果膨大期IP通过降低LCP和LSP来提高对弱光的利用效率,降低R_d来增加花生体内营养物质的有效积累。     

Field performance of potato (Solanum spp.) cuttings in the warm tropics: Influence of planting system,hilling, density and pruning

Growing potatoes from cuttings for seed and table potato production has great potential in Asia. There is limited information available explaining the agronomic methodology of growing cuttings in the field. This research was conducted to assess the importance of 4 management variables on the growth and tuber yield of cuttings. Three planting systems were evaluated with and without hilling. Only hilling significantly improved yields and increased tuber number per plant by 50%. Hilling also reduced tuber greening. Increasing plant population from 40,000 to 100,000 per hectare resulted in a yield increase of at least 50%, however average tuber size decreased. Pruning of the apical shoot at or after transplanting did not improve branching, canopy cover or tuber yield. Yields from cuttings were equal to or greater than the tuber seed grown control treatments. Yields ranged from 15 to 20 t/ha which is acceptable for the warm growing conditions. These results show the potential of using cuttings in commercial growing of potatoes in the warm tropics where tuber seed is difficult to obtain and maintain.