In vitro culture of tissues,cells and protoplasts of Trifolium alexandrinum L. (Egyptian clover)

Summary Callus induction derived from root, hypocotyl and cotyledon explants were investigated for four cultivars of Trifolium alexandrinum L. The Murashige & Skoog (1962) medium containing 2.0 mg/L NAA and 0.5 mg/L BAP was able to induce callus from different explants. A wide range of culture media were tested to determine the morphogenetic potential of different callus types derived from different explant types. Shoot morphogenetic development was observed with the cultivars Sakha 4 and Giza 10. Cell suspension cultures were established from hypocotyl derived callus. Methods for isolation and culture of protoplasts from cotyledons are described.     

Genetic relationships between attributes in sugarcane clones closely related to Saccharum spontaneum

Summary Saccharum spontaneum is being used in sugarcane breeding programs in attempt to improve characteristics such as ratooning ability and stress tolerance. A population of F₁ (Saccharum officinarum or commercial variety x S. spontaneum) and F₁ x F₁ sugarcane clones was evaluated for sugar yield and a range of yield components in a plant and two ratoon crops. The aim was to determine genetic correlations between attributes in clones with a large component of S. spontaneum, that could be used to help derive appropriate selection indices in such populations.There were close associations between the same attributes measured in different crop-years and the associations between different attributes were generally similar across crop-years. Stalk number and fibre content were positively correlated, as were stalk weight and CCS. The latter two attributes (which are low in S. spontaneum but high in S. officinarum) were negatively correlated with the former two (high in S. spontaneum, low in S. officinarum). Sugar yield was more closely associated with stalk weight and CCS than with stalk number but became more closely associated with stalk number with successive ratoon crops.CCS was positively correlated (r_g=0.55) with cane yield in the plant crop but showed a small negative correlation with cane yield (r_g=–0.20) in the second ratoon crop. CCS (measured in any crop) also had a negative correlation with cane yield in the ratoon crops expressed as a percentage of plant cane yield. This suggests that CCS is negatively correlated with levels of traits contributing to ratooning ability. Intensive selection among such populations for CCS without consideration of ratooning performance may reduce the frequency of favourable specific ratooning characteristics.Abbreviations CCS commercial cane sugar     

Tissue and cell culture as aids to sugarcane breeding. II. Performance and yield potential of callus derived lines

Summary Thirteen callus derivatives from the sugarcane (Saccharum sp. hybrid) varieties F156 and F164 were studied to investigate the potential of tissue culture methods to generate superior germplasm for plant breeding in a field trail conducted at a single location. Comparisons between callus derivatives and donors were made for 9 characters, viz. cane yield, sugar yield, stalk number, length, diameter, volume, density, weight/stalk, and percent fiber. Statistical analyses were run, which involved stepwise multiple regression, broad-sense heritability (H), genetic advance (G). Esterase zymogram of superior callus derivatives was examined. 70–6132 was 32, 34 and 6% higher than its donor (F164) in cane yield, sugar yield and stalk number, respectively. The differences between them for the first two characters reached the 5% probability level. 70–6132 was also higher for these 3 characters than F160, the No. 1 commercial variety, by 20, 16 and 8%, respectively. 70–6136 ranked next only to 70–6132. Its grand means for these 3 characters outdid the parental (F164) means by 21, 24 and 3%, respectively. 70–6069 was significantly higher in stalk diameter and volume than most of the callus derivatives but not higher than its donor (F156). The performances of other derivatives were either similar or inferior to both their donors and F160. Stalk number, stalk length and weight/stalk accounted for 43, 29 and 18% of the variation of cane yield, respectively. H values for the 7 characters (stalk density and percent fiber were not included) ranged from 31 (stalk length) to 66% (stalk volume). G/\-x 100 for the 7 characters ranged from 3.3 (stalk length) to 18.6% (sugar yield). 70–6132 had two bands missing, 70–6069 had two bands more whereas those of 70–6136 showed no visible change, in esterase zymogram as compared with the donors. Due to the improved yield and the genetic changes revealed by the isoenzyme patterns in callus derived lines, tissue culture methods can be used to create superior varieties for agricultural use.     

粤糖系列甘蔗品种产量因子间相关和通径分析

以粤糖系列10个甘蔗品种的历年选育试验数据为材料,利用相关分析、多元回归、通径分析和决定系数等方法,分析蔗茎产量与其构成因子的密切程度,以及各因子对产量的相对贡献大小。简单相关分析结果表明,蔗茎产量与有效茎数和茎长呈极显著正相关(0.643**和0.650**),与茎径相关不显著(0.025),有效茎数和茎长呈极显著正相关(0.234**),茎径与有效茎数和茎长呈极显著负相关(-0.416**和-0.257**);偏相关分析结果表明,蔗茎产量与其构成因子都呈极显著正相关(0.854**、0.836**和0.741**);多元回归方程为y=0.235x1+0.370x2+48.795x3-202.674 (ry.123=0.924**),F值均达到极显著水平;通径分析和决定系数分析结果表明,有效茎数对蔗茎产量的直接效应和直接决定系数都最大(0.696和0.485)。以上分析都表明,相对于茎长和茎径,有效茎数与蔗茎产量关系最密切,对蔗茎产量的贡献最大,增加有效茎数可显著提高蔗茎产量。有效茎数是影响蔗茎产量的关键因素,是品种高产选育和高产栽培的主攻方向,甘蔗高产育种中,应首先考虑对有效茎数的选择,其次考虑对茎径和茎长等影响蔗茎产量重要因素的选择。     

Limited contribution of water availability in genotype-by-environment interaction in sugarcane yield and yield components

Water deficit is an important abiotic stress factor limiting sugarcane production. Understanding the effect of water deficit on cane yield, yield components and genotype × environment (G × E) interaction can aid in selecting genotypes that are adapted to water deficit conditions. In this study, response of cane yield and yield components of 10 sugarcane genotypes grown under 3 irrigation treatments—fully irrigated, semi-irrigated and rainfed—was examined across 3 locations and 3 crop-years within each location. Cane yield reduced by 32% and 9% in the rainfed and semi-irrigated treatments, respectively, compared to the fully irrigated treatment. Genotypic variation was highly significant for cane yield and yield components in all three irrigation regimes. Cane yield in the rainfed treatment showed significant genetic correlation with stalk diameter (r_g = 0.68), leaf number (r_g = 0.64), node number (r_g = 0.67) and stalk number (r_g = 0.68). Genotype × irrigation variance was negligible compared to genotype, genotype × location and genotype × crop-year variances. Commercial genotypes had higher yield in most environments except in low-yield potential environments, which caused a significant genotype × location × irrigation effect, suggesting opportunities for improving sugarcane productivity in these environments.     

Damage assessment for selection of resistance to the spotted stalk borer and genetic correlations for resistance and yield components in sugarcane

We conducted an assessment of the stalk damage of the spotted borer, Chilo sacchariphagus (Bojer), on 65 cultivars and elite clones under natural infestation conditions in Réunion Island, with the objectives (i) of comparing seven damage measures on the basis of their quantitative genetic parameters and (ii) of studying the relationships between borer resistance and sugarcane yield components. The heritabilities of the damage measures related to counts of borer exit holes were low, whereas the heritabilities of the damage measures related to bored stalks or internodes were high and similar amongst them. The percentage of bored stalks exhibited high phenotypic and genotypic correlations with the other damage measures, and appeared as the best cost effective damage measure. Genetic correlations revealed a negative relationship between resistance to borer and cane yield, due to a relationship of stalk damage with stalk length and (in a lesser extent) with stalk number. No significant genetic relationship between resistance and sugar content parameters was observed.     

Inter-relationships among cane yield and commercial cane sugar and their component traits in autumn plant crop of sugarcane

Seventeen diverse clones of sugarcane (Saccharum spp.) (7 early, 6 mid season and 4 late) were planted in October 1991 and 1992 in flooded (FE) and non flooded (NFE) environments for evaluation of cane yield, commercial cane sugar (CCS), internode length, internode number, stalk length, stalk thickness (circumference), stalk number, sugar recovery, and stalk weight. Cane yield showed significant positive phenotypic correlation coefficient (PCC) with stalk number in FE (P ≤ 0.05) and NFE (P ≤ 0.01). Stalk length had a significant positive PCC with stalk weight in both environments, and with internode length in FE (P ≤ 0.05). Commercial cane sugar also expressed significant positive PCC with cane yield in both environments (P ≤ 0.01), but with stalk number only in NFE (P ≤ 0.05). Genotypic correlation coefficients were generally in the same direction as PCC but higher in magnitude. In both environments, stalk number and stalk weight had relatively high positive direct effects on cane yield. However, flooding tended to enhance the direct effect of stalk weight and diminish the direct effect of stalk number on cane yield. Only cane yield and sugar recovery had high direct effects on CCS. Selection for improvement of cane yield can be based on stalk number and stalk weight in both environments. High yielding clones can be further screened for more sugar recovery to improve CCS. This revised version was published online in July 2006 with corrections to the Cover Date.     

用灰色关联法对11个甘蔗新品系主要数量性状与产量关联度的分析

为探索甘蔗主要数量性状对产量的影响程度，应用灰色关联度分析方法，对参加2005—2006年区域试验的11个甘蔗新品系的主要数量性状与产量的关联度进行了分析。结果表明：甘蔗主要数量性状与产量之间的关联度由高到低依次为公顷含糖量、茎长、茎径、萌芽率、单茎重、有效茎、分蘖率，说明甘蔗公顷含糖量和茎长是影响甘蔗产量的主要因素，为甘蔗育种提供了重要的理论依据     

Effect of Formative Phase Drought on Different Classes of Shoots, Shoot Mortality, Cane Attributes, Yield and Quality of Four Sugarcane Cultivars

Field experiments were conducted at Coimbatore, India to study the effect of three levels of drought (severe, moderate and no drought) during the formative phase (60–150 days after planting; DAP) of sugarcane on the tillering, the conversion of shoots to millable canes, cane attributes and the quality of different classes of shoots in four sugarcane cultivars (Co 8021, Co 419, Co 8208 and Co 6304)_the different classes of shoots studied were: mother shoots (which emerged 0–30 DAP), early tillers (30–60 DAP), mid‐season tillers (60–150 DAP) and late tillers (150 DAP). The results indicated that drought during the formative phase reduced the total number of shoots and their conversion to millable canes at harvest. Drought also reduced the cane length, number of inter‐nodes and single cane weight of different classes of shootsand the subsequent total cane yield. Irrespective of drought treatments, Co 8021, a high‐tillering, thick‐stalked cultivar, gave the highest cane yield despiteits higher shoot mortality, while Co 8208, a low‐tillering, thin‐stalked cultivar, gave the lowest cane yield despite its lower shoot mortality. Thus a moderate level of shoot mortality is clearly necessary to obtain higher millable canes and subsequently higher cane yield. Mother shoots and early tillers together contributed most of the total number of millable canes (84.5 %) and of the total cane yield at harvest (86.2 %). The contribution of late tillers to the number of millable canes and cane yield was, however, negligible, especially in cultivars Co 6304 and Co 8208. There was a gradual reduction in stalk attributes such as cane length, number of internodes, single cane weight and commercial cane sugar percentage as the physiological age of shoots decreased. This study emphasizes the need for a cultivar with the optimal characteristics of early tillering (like Co 8021 and Co 6304) and maximum conversion to millable canes (like Co 8208) and provides information relevant to breeders making decisions on crossing programmes to produce improved cultivars for drought conditions.     

Electrophoretic patterns of acid soluble proteins and active isoforms of peroxidase and polyphenoloxidase typifying calli and somatic embryos of two reputed date palm cultivars in Morocco

Summary When subjected to micropropagation by tissue culture, the two reputed cultivars of date palm (Phoenix dactylifera L.); Bou-Sthammi noire, resistant to Bayoud disease and Bou-Feggous, of high fruit quality, give rise to three types of calli, called white and root-forming callus, hyperhydric and degenerating callus and friable and embryogenic callus. All explant sources, calli and germinated embryos were analysed by denaturing polyacrylamide gel electrophoresis (SDS-PAGE) for acid soluble protein composition. Phenol-oxidizing enzymes; peroxidase and polyphenoloxidase, were also, evaluated and the isoforms separated by polyacrylamide gel electrophoresis. When compared with the explant and germinated embryos, embryogenic calli of the two date palm cultivars could be identified by a concentrated polypeptide of molecular weight 27 500 and polypeptides of molecular weights 70 000 and 11 500. Hyperhydric and degenerating callus contained the polypeptide exhibiting the molecular weight 32 000. Embryogenic calli showed high levels of soluble, ionically and covalently bound peroxidases. The soluble acidic isoperoxidase of R _f 0.60, revealed in these calli and germinated embryos could be a marker of the two tissues. White and root-forming calli of Bou-Feggous cultivar were typified by soluble acidic isoperoxidases with high mobility (R _f 0.75) and anodic ionically wall-bound polyphenoloxidases similar to those of the explant sources. Polyphemoloxidase activities detected in calli and embryos were very low when compared with those of explants. Used as an early test to screen embryogenic calli of date palm, acid soluble proteins, peroxidase and polyphenoloxidase data could lead to introduce lightening and economy in the tissue culture technique.     

Agrobacterium-mediated Cry1A(b) gene transfer in Punica granatum L. cv. Kandhari Kabuli using different In Vitro regeneration pathways

Three different regeneration systems, viz. regeneration through callus cultures using embryonic explant, direct regeneration using shoot bud/nodal segments as explant and regeneration through cell suspension culture using cotyledonary explant (for the induction of transgenic callus for suspension culture) were evaluated to see their effect on transfer of Cry1A(b) gene to Punica granatum L. cv. Kandhari Kabuli through Agrobacterium mediated transformation. Pre-conditioning and co-cultivation durations had a marked effect on transformation frequency of different explants. Out of different explants used (embryo, shoot bud, and cotyledon) for different regeneration systems cotyledonary explant showed highest putative transformation frequency (13.54%) inducing callus on selective medium for carrying out cell suspension culture to regenerate transgenic shoots. Despite of the highest transformation frequency obtained from the cotyledon explant, the plating efficiency of the transgenic cells generated through the transgenic callus (callus formed from the cotyledonary explant) during cell suspension culture was found to be very low (0.7%). Thus the plating efficiency has also played worth mentioning role in the regeneration of transformants following cell suspension culture. Among the three regeneration systems, regeneration through callus cultures using embryonic explant was found to be best for regeneration of transformants. The highest per cent regeneration of 23.33 was obtained from the putative transgenic embrogenic calli. Successful genetic transformation in the transformed plantlets was confirmed by PCR analysis. The transformation system thus developed is valuable and may be used to produce insect resistant trees.     

果蔗健康种苗田间效果评价

甘蔗宿根矮化病(ratoon stunting disease,RSD)和花叶病(sugarcane mosaic disease,SMD)是引起果蔗种性退化的主要原因,其有效的防治方法是种植果蔗健康种苗。为评价果蔗健康种苗的田间效果,笔者进行果蔗健康种苗与其普通种茎苗新植田间比较试验,并应用分子检测技术对种苗甘蔗宿根矮化病菌和甘蔗花叶病病原病毒（甘蔗花叶病毒、高粱花叶病毒及甘蔗线条花叶病毒）进行检测。结果表明,果蔗健康种苗较其普通种茎苗蔗茎产量增产23.85%,甘蔗蔗糖分提高0.36个百分点;茎长增长20.6 cm、节间增长2.47 cm、单茎重增重0.65 kg;萌芽快,萌芽率提高24.6个百分点,分蘖率提高18.4个百分点,但两者的有效茎数差异不明显。健康种苗未检测出甘蔗宿根矮化病菌及甘蔗花叶病毒、高粱花叶病毒、甘蔗线条花叶病毒。研究表明,果蔗健康种苗具有显著的增产提质效果。     

Somaclonal variation in sugarcane through tissue culture and evaluation for quantitative and quality traits

Eight genotypes of Saccharum officinarum were crossed with Saccharum spontaneum and 14 genotypes of S. officinarum were crossed with Erianthus arundinaceus. A total of 39 hybrids were evolved. These 39 hybrids were raised in the field and used as donor clones for in vitro culture studies. Plantlets were regenerated from 1-month-old callus. The grown up plants were transplanted to well prepared field, to study the variations generated for the biometric as well as for biochemical characters. There were significant differences between the donor clones and their sub clones for all the character of interest. The somatic segregation was gradual and wider, showing a range of divergence from the mean towards the end of the scale. Fifty-one sub clones were selected with commercial potential which have 13% fibre, 200 cm stalk length, 10 cm internode length and pure obtainable cane sugar per cent of 10.     

氮肥减量条件下间作绿豆压青对甘蔗生长及氮代谢的影响

以甘蔗单作常规施氮量为对照（CK）,设氮化肥减量20%+间作绿豆压青（A）、氮化肥减量40%+间作绿豆压青（B）和氮化肥减量60%+间作绿豆压青（C）3个处理,通过测定甘蔗农艺性状、蔗茎产量和甘蔗叶片氮代谢相关生理生化指标,研究氮肥减量条件下间作绿豆压青对甘蔗生长及氮代谢的影响。结果表明,间作绿豆影响新植蔗分蘖,分蘖率显著低于CK,但对甘蔗有效茎数影响不显著。新植蔗产量表现为A>B>CK>C。氮化肥减量条件下间作绿豆压青对宿根蔗发株率、株高、有效茎数、甘蔗茎径有促进作用。宿根蔗蔗茎产量表现为A>B>C>CK。2年的甘蔗蔗糖分含量表现为C>B>A>CK。氮化肥减少20%条件下间作绿豆压青对提高甘蔗叶片谷氨酰胺合成酶、硝酸还原酶活性和游离氨基酸、可溶性糖含量有促进作用。综合甘蔗农艺性状、蔗茎产量、氮代谢相关指标测定结果和经济效益的表现,试验以氮化肥减量20%+间作绿豆压青的A处理最优。     

Forage quality of genetically diverse alfalfa germplasms at four phenological growth stages

Summary Forage quality of various alfalfa (Medicago sativa L.) cultivars has been determined under different environmental conditions, and numerous trials with alfalfa have documented an inverse relationship between forage quality and maturity. Little information is available, however, regarding the comparative forage quality of the germplasm sources from which most USA cultivars were developed. We compared forage quality of these germplasm sources at four phenological stages under disease- and insect-free conditions in a greenhouse. Germplasm sources (cultivars) tested were: Indian (Sirsa #9), African (African), Peruvian (Hairy Peruvian), Flemish (DuPuits), Turkistan (Lahontan), Chilean (Kansas Common), M. varia (Grimm), and Ladak (Ladak). Four harvests were taken and forage was separated into four phenological stages: vegetative, early bud (1–3 buds-per-stem), late bud (>3 buds-per-stem), and bloom. The germplasm source X phenological stage interaction was significant for crude protein (CP) and in vitro digestible dry matter (IVDDM) concentrations. M. varia showed the least decline in IVDDM and CP with increasing maturity. M. varia had higher IVDDM than did African and Indian at late bud and bloom stages. Indian and Flemish had higher CP than did Turkistan and Peruvian at late bud and bloom stages. Alfalfa germplasm sources differ in forage quality when comparisions are made within similar stages of phenological development.Joint contribution of the Dept. of Agronomy and USDA-ARS, Kansas Agricultural Experiment Station, Manhattan, KS 66506, USA. Contribution no. 90-475-J.     

宁糯芋1号茎尖离体培养条件优化

为丰富福建省优质芋种源，加快优良品种推广应用，以‘宁糯芋1号’块茎顶芽和侧芽为外植体，运用茎尖分生组织培养获得了不定芽。在正交试验基础上，根据响应面分析法中心组合试验，以不定芽增殖系数为响应值，对TDZ、温度2因素进行优化，结果发现：与6-BA相比，TDZ更适于芋茎尖诱导丛芽，在MS培养基中附加0.1~0.2 mg/L的TDZ能显著促进芋茎尖的萌动，成苗率达76.7%~80.0%，经芋花叶病毒(DMV)检测试剂盒的ELISA检测表明脱毒率为90%；响应面优化结果表明，‘宁糯芋1号’不定芽继代增殖的最佳培养条件为 MS+TDZ0.31 mg/L，培养温度30.32℃，增殖系数预测值为9.08，验证得到的实际值为8.86。利用响应面方法可有效优化‘宁糯芋1号’不定芽继代增殖培养条件。     

应用GGE双标图分析甘蔗品种(系)的产量和品质性状

采用GGE双标图分析7个甘蔗参试品种在7个试点的产量和品质性状。结果表明, 云蔗05-51(YZ05-51)为单茎产量高且稳定性强的品种, 福农39(FN39)和柳城03-1137(LC03-1137)的单茎产量较高, 但稳定性较差; 福农38 (FN38)、粤甘35 (YG35)和新台糖22 (ROC22)有效茎数较高, 但稳定性较差; 福农39 (FN39)和云蔗05-51 (YZ05-51)为蔗茎产量较高且稳定性强的品种, 福农38 (FN38)和柳城03-1137 (LC03-1137)蔗茎产量高, 但稳定性较差; 福农39 (FN39)和赣南02-70 (GN02-70)为甘蔗蔗糖分较高且稳定性强的品种, 云蔗05-51 (YZ05-51)和福农38 (FN38)甘蔗蔗糖分较高, 但稳定性较差; 福农39 (FN39)为产糖量较高且稳定性较强的品种, 福农38(FN38)、云蔗05-51 (YZ05-51)和柳城03-1137 (LC03-1137)的产糖量较高、但稳定性较差。云南瑞丽和云南临沧2个试点单茎产量的代表性和区分力较强; 云南保山和广西来宾2个试点有效茎数的代表性和区分力较强; 广西崇左和云南临沧2个试点蔗茎产量的区分力较强; 广西百色和柳州2个试点甘蔗蔗糖分的区分力较强; 广西百色和云南临沧2个试点产糖量的区分力较强。     

Using logistic regression models for selection in non-replicated sugarcane breeding populations

Increasing selection efficiency in un-replicated populations has remained a challenge to sugarcane breeders due to the effects of genotype by environment interaction and competition among plots. Therefore studies aimed at exploring models to improve selection efficiency are required. At the South African Sugarcane Research Institute, the Stage II selection populations are planted to un-replicated plots. Visual selection, which is known to be subjective, is used to determine the genotypes advanced. Although path coefficient analysis has identified important yield components, there is little use of that knowledge to enhance selection. This study demonstrates the use of logistic regression model as a statistical decision support tool to enhance selection in un-replicated populations. The logistic regression model used stalk number, stalk height, stalk diameter and estimable recoverable crystal (ERC) % cane to predict sugar yield. The data were collected from Stage II populations across regional breeding programs and analysed using the logistic procedure of Statistical Analysis System. The Likelihood Ratio, Score and Wald statistics were highly significant (P < 0.0001) indicating the robustness of the models. Stalk number is the most influential component to sugar yield followed by diameter, height and ERC % cane. The coefficients of the yield components varied across different programs indicating the potential of the analysis to determine yield component combination. Genotypes selected using the models produced significantly higher trait values than those rejected. The logistic regression models should enhance selection efficiency in un-replicated populations as well as provide for the evaluation of breeding populations and trait combinations across regional breeding programs.     

大花绣球‘无尽夏’组培苗叶片再生植株的研究

为建立大花绣球‘无尽夏’规模化无性繁殖和高效遗传转化体系,以‘无尽夏’组培苗叶片为外植体,研究叶位、暗培养时间及不同激素组合等因素对叶片诱导形成愈伤及分化不定芽的影响。结果表明,‘无尽夏’组培苗植株中上部叶片的愈伤诱导效果好,适宜的外植体取样叶位为第3~6位叶片。初始暗培养有利于叶片形成愈伤,暗培养15~25天的效果最佳。诱导‘无尽夏’组培苗叶片形成愈伤的适宜培养基为MS+CPPU 3.0 mg/L+IBA 0.1 mg/L,其愈伤诱导率达到98%以上;愈伤增殖与不定芽分化培养基为MS+6-BA 1.0~2.25 mg/L+IBA 0.1 mg/L。     

播期和种植密度对早熟高糖甘蔗新品种‘云蔗05-51’产量及其构成因素的影响

为明确甘蔗新品种云蔗05-51的高产高效栽培技术,加快该品种在生产上的大面积推广应用。于2014-2016年度在陇川弄门基地,对云蔗05-51以4个播种期和4个种植密度处理,布置二因素随机区组试验,研究播期和种植密度对‘云蔗05-51’的产量及其构成因素的影响。结果表明：播期对‘云蔗05-51’的茎径、有效茎数及蔗茎产量有显著影响,但对株高和锤度影响不显著;种植密度对‘云蔗05-51’的有效茎数、锤度和蔗茎产量有显著影响。蔗茎产量在1月20播种最高达到150.70t/hm₂,过了1月20日后随着播期的推迟产量增减差别不大;在种植密度B₁(150000芽/hm₂)时蔗茎产量达到最高值127.25t/hm₂,蔗茎产量随着种植密度的减少亦相应的减产。从播期和密度的交互效应来考虑‘云蔗05-51’最佳的播期和种植密度分别是1月20日播种,下种种植密度为B₁(150000芽/hm₂)。