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     

甘蔗新品系的DTOPSIS法综合评价

以新台糖22号（ROC22）为对照,对9个甘蔗新品系进行1年新植和2年宿根比较试验,利用方差分析和DTOPSIS法进行评价。结果表明,9个参试品系中桂糖11-80、桂糖11-2142和柳糖10-21的2年宿根黑穗病发病率高于ROC22,其他品系则低于ROC22,其中桂糖10-517第1年宿根发病率为0,桂糖10-434 2年宿根发病率均为0。通过DTOPSIS法综合评价,理想解相对接近度（C_i）低于ROC22的品系有桂糖10-3006和桂糖10-517,表现出低产和低糖等特点;C_i高于ROC22的品系有桂糖10-2018、桂糖10-434、河糖11-145和桂糖10-2003,表现出高产高糖且抗逆性强等优良特性,适合在广西崇左蔗区及气候条件相似的蔗区推广种植。     

Screening for and heritability of flood-tolerance in the Florida (CP) sugarcane breeding population

Summary An experiment screening for flood-tolerance and estimating the heritability of flood-tolerance was conducted on 160 sugarcane clones in the Canal Point, Florida, USA sugarcane breeding population. Clones were grown in two environments, a drained control and a continuous, five-month flood. The test ran for two crop years, plant-cane and first ratoon. A wide range of production was observed, with some clones dying out after the first year. Several clones had two-year mean cane production in flood that was 70% of their production in control. Heritabilities calculated by parent-offspring regression ranged from 0.29 to 0.51.     

甘蔗苗期大螟幼虫空间格局的地统计学分析

为明确大螟幼虫在甘蔗苗期的空间格局,2012年在云南省农业科学院甘蔗研究所科研示范基地开展了甘蔗苗期大螟为害枯心苗调查,并应用地统计学方法进行空间格局分析。结果表明：新植蔗虫口密度（1.07头/点）明显低于宿根蔗（1.91头/点）,新植蔗变异系数、峰度和偏度均较宿根蔗大,表明大螟在宿根蔗较新植蔗发生重,且新植蔗田较宿根蔗田有更高的聚集度。在半变异函数理论模型模拟方面,新植蔗田在4个方向均为球形模型,宿根蔗田在45°和90°方向为球形模型、0°方向为高斯模型、135°方向属随机分布,表明大螟幼虫整体上呈聚集分布,但新植蔗田聚集度较宿根蔗田高。在相关性方面,新植蔗田和宿根蔗田均在0°和45°方向上有中等的空间相关性,相关距离宿根蔗明显大于新植蔗,表明宿根蔗田的大螟幼虫空间相关性较新植蔗田强。通过Kriging插值模拟图可清晰看出,新植蔗大螟幼虫在蔗田边缘发生严重,虫源主要来自周边蔗田,宿根蔗大螟幼虫在田间的螟虫发生点多且均匀,虫源主要来自自身蔗田。     

糖能兼用甘蔗品种（系）对不同播种密度的响应

为了解不同糖能兼用甘蔗品种（系）在不同播种密度条件下的生产性能表现,为今后进行能源甘蔗品种推广应用提供参考。对来自国内外的5个糖能兼用甘蔗品种（系）在5种不同播种密度下进行1年新植1年宿根种性比较试验。结果表明,不同播种密度水平之间的平均生物产量、蔗茎产量、蔗糖产量和总可发酵糖产量差异均不显著;B1、B8、GT26、GT97/69、GT22等品种（系）之间在生物产量、蔗茎产量、蔗糖产量、总可发酵糖产量和株高、茎径、有效茎数等产量构成因子方面的差异达到极显著水平;GT97/69、B1对播种密度反应比较敏感,其最适宜的播种量分别是每公顷12万芽和13.5万芽,其他品种反应则不敏感。甘蔗的产量主要由品种（系）的种性决定,不同品种对不同的播种密度反应不同,甘蔗新品种在推广应用之前应在不同栽培管理水平和环境条件下进行播种密度试验,确定比较合理的单位面积播种量。     

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。     

干旱条件下单用草甘膦或添加营养元素作为甘蔗化学催熟剂的效应

中熟甘蔗品种桂糖15号在生长后期分别用草甘膦、 草甘膦+KH2PO4、 草甘膦+H3BO 3和草甘膦+KH2PO4+H3BO3进行叶面喷施。 结果表明： 在严重干旱的条件下, 单 用草甘膦处理对甘蔗生长和蔗茎糖分积累都不利, 而添加营养元素的处理, 尤其是草甘膦 +H3BO3处理, 可缓解草甘膦对生长代谢的抑制效应, 使叶片Mg2+-ATP酶和NADP -     

绿豆/黑豆压青还田下减量施肥对宿根甘蔗产量和主要农艺性状的影响

为探讨绿豆/黑豆还田和减施化肥条件下,间作绿肥压青还田对宿根甘蔗生长的影响及绿肥还田和有机肥施用对化肥的替代作用。试验设计了常规施肥（CK）、化肥减施25%+12%营养元素当量绿豆绿肥还田+13%营养元素当量有机肥（H-LY）、化肥减施25%+全量绿豆还田（H-LQ）、化肥减施25%+25%营养元素当量有机肥（H-Y）、化肥减施25%+25%营养元素当量黑豆绿肥还田（H-HD）和化肥减施25%+全量黑豆还田（H-HQ）6个处理。结果表明,与CK处理相比,宿根蔗间作绿豆和黑豆压青还田对甘蔗株高、有效茎数和单茎重没有显著影响,所有处理的蔗茎产量与CK处理无显著差异,说明宿根蔗间作绿豆和黑豆绿肥压青还田、当量有机肥施用均可以替代25%的甘蔗化肥。     

Potassium nutrition for improving stubble bud sprouting,dry matter partitioning,nutrient uptake and winter initiated sugarcane (Saccharum spp. hybrid complex) ratoon yield

A field experiment was conducted for two crop cycles during 2003–2005 and 2004–2006 at Indian Institute of Sugarcane Research, Lucknow to improve bud sprouting, dry matter accumulation (DMA), nutrient uptake and ratoon yield by using potassium fertilizer. Potassium (K) fertigation in standing plant cane increased the number of buds per stubble and number of stalks in ratoon cane. K content of stubble increased by 16.7% with K fertigation. The content of reducing sugars in buds at the time of ratoon initiation improved significantly with K fertigation. It improved dry matter accumulation, number of millable canes, individual cane weight, ratoon cane and sugar yields. Thus, it could be concluded that application of 66 kg K ha^?1 with irrigation water in standing plant cane before harvest improved bud sprouting, dry matter accumulation and nutrient uptake in ratoon crop. Irrigation in standing plant cane increased ratoon cane (69.9 t ha^?1) and sugar yields (7.6 t ha^?1). This increase for ratoon cane and sugar yield was 8.7 and 5.55%, respectively over the control. Further, it increased ratoon cane yield by 15.21% (74.1 t ha^?1) and sugar yields by 13.9% (8.2 t ha^?1) with K fertigation over the control. Thus, K nutrition holds great promise for improving growth of ratoon cane and sugar yields.     

新引进甘蔗品种比较试验

为了探明新引进甘蔗品种的种性表现,采用品比试验方法,于2010-2011年在广东省增城市宁西华南农业大学基地进行新引进甘蔗品种比较试验。结果表明,在8个参试品种中,Q200B、Q189和Q208综合表现较好,表现为早熟或中早熟、高糖、稳产、宿根性好、农艺性状优良,新宿11月中旬至12月中旬平均蔗糖分含量分别为14.53%、15.11%和14.23%,分别比对照‘新台糖16号’降低0.44个百分点、提高0.14个百分点和降低0.74个百分点,分别比对照‘新台糖22号’提高0.03个百分点、提高0.61个百分点及降低0.27个百分点;蔗茎产量分别为110829 kg/hm2、105830 kg/hm2和92674 kg/hm2,分别比对照‘新台糖16号’增产29.1%、23.3%及8.0%,分别比对照‘新台糖22号’增产2.1%、减产4.3%和7.2%;含糖量分别为16110 kg/hm2、15999 kg/hm2和13186 kg/hm2,分别比对照‘新台糖16号’增糖25.4%、24.5%及2.6%,比对照‘新台糖22号’增糖0.4%、减糖0.2%和17.8%;Q155、Q151表现特早熟、高糖,但中小茎、蔗茎产量低;Q190表现丰产潜力大、前期生长极快,但迟熟低糖;Q157、Q96的综合表现最差。并对参试品种的利用意向提出了建议。     

甘蔗一个生产周期株高生长量与气象因子的关系

利用柳州市沙塘国家农业气象试验站一级站2010—2012年甘蔗生长发育观测资料与主要的气象因子,重点分析了新植蔗、第一年宿根蔗和第二年宿根蔗旬伸长量与旬降水量、旬平均温度、旬平均日照时数的关系,并对甘蔗旬伸长量与气象因子进行相关分析。结果表明：甘蔗伸长量与旬降水量有较好的对应关系,该旬降雨量大,甘蔗旬伸长量就高,与当地降水规律重合,通过相关性分析,气象中的水分因子,降水量、相对湿度、旬平均水汽压与新植蔗、第一年宿根蔗和第二年宿根蔗旬伸长量呈显著或者极显著的正相关关系;旬平均温度与新植蔗旬伸长量呈正相关关系,但是不显著,与第一年宿根蔗和第二年宿根蔗旬伸长量呈显著的正相关关系;旬平均日照时数峰值对应旬伸长量低值,通过相关性分析旬平均日照时数与新植蔗、第一年宿根蔗和第二年宿根蔗相关性不显著,说明水分因子是决定甘蔗高度的关键气象因子。     

5种农药防治甘蔗螟虫田间药效评价

为研究不同杀虫剂对甘蔗螟虫的防治效果及使用技术,筛选有效防治甘蔗螟虫的理想杀虫剂,采用5种杀虫剂防治甘蔗螟虫进行田间药效试验,评价分析各种农药对甘蔗螟害株和螟害节的防治效果以及对甘蔗糖分和产量的影响。结果表明,不论新植蔗还是宿根蔗,与空白对照相比,各药剂处理对甘蔗螟虫均有不同程度的防治效果,甘蔗糖分和产量均有所增加;其中5%异丙特丁硫磷颗粒剂75 kg/hm²对螟虫的防治效果最好,螟害株防治效果和螟害节防治效果分别为76.59%和87.83%,处理后甘蔗糖分和实测产量也均为最高,分别达15.72%和101382.15 kg/hm²,较对照增加0.64%和7832.40 kg/hm²;3.6%杀虫双颗粒剂90 kg/hm²次之,螟害株防治效果、螟害节防治效果、甘蔗糖分和产量分别为72.34%、84.26%、15.66%和100234.35 kg/hm²,甘蔗糖分和产量分别较对照增加0.58%和6684.60 kg/hm²。因此,在甘蔗大培土期,使用5%异丙特丁硫磷颗粒剂75 kg/hm²或3.6%杀虫双颗粒剂90 kg/hm²可有效防治甘蔗螟虫,增产增糖效果明显。     

Effect of tissue culture explant source on sugarcane yield components

Clonal propagation of sugarcane(interspecific hybrids of Saccharum)is conducive to spread of systemicdiseases, such as ratoon stunting disease,caused by Leifsonia xyli subsp. xyli. This important disease iscontrolled by obtaining and plantinghealthy seed-cane. In Louisiana, commercialseed-cane initially produced through tissueculture is available to sugarcane farmersand is being widely planted. Long-termacceptability of this seed-cane productionmethod depends on the production of healthyplants that do not differ significantly inphenotypic and yield characteristics fromthe clones originally selected and releasedas commercial cultivars. To determinewhether tissue culture affects yield or itscomponents, three cultivars, CP 70-321, LCP85-384, and HoCP 85-845, were compared inthree successive crops initially plantedwith stalks from three sources: plantsderived from callus culture of the leafroll above the apical meristem, directregeneration from the apical meristem, andconventional bud propagation. Stalks ofplants derived from both explant sourceswere typical of seed-cane farmers wouldpurchase for planting that had beenpreviously rogued for phenotypic variantsand increased by bud propagation.Differences in yield components amongtissue culture explant sources and budpropagated cane only occurred in CP 70-321.Stalk diameter and stalk weight were lowerand stalk population was higher for plantsderived from leaf roll callus compared tobud propagated cane. Yield components weresimilar for plants derived from an apicalmeristem and bud propagation. Individualplant phenotypic variants resulting fromsomaclonal variation were not observed inany of the cultivars derived from eitherexplant source. In summary, genotype andexplant source affected persistent, uniformphenotypic variation resulting from tissueculture that changed some yield components. However, apical meristem culture wassuitable for production of seed-cane, assugarcane derived by meristem culture ofthree cultivars did not differsignificantly from the original germplasmfor any measured yield trait.     

A technique for minimising confounding of genotype x year and genotype x crop type effects in sugarcane

Summary Genotype x year (G x Y) and genotype x crop (G x C) interactions may be confounded in sugar cane when data is obtained from the plant crop and/or from ratoon crops in successive years. A technique to minimise the effects of confounding of the G x C interaction with the G x Y interaction is presented. The mean yield of cane from neighbouring farms was used as an indicator of the year (environment) effect. It was used to re-analyse yields from three experiments comparing six genotypes grown over a plant crop and three ratoons. Two experiments were grown under rainfed conditions and one experiment was irrigated. The confounded interactions were partitioned into a linear contrast on the farm yields (a year effect) and a crop effect that was the remainder. When the yields adjusted for the farm yield effects were compared with original yields of cane, yields of plant and first ratoon were reduced and those of third ratoon were increased. There were only minor changes in the ranking of genotypes on yield. It was concluded that the re-analysis using farm yield showed that the confounding effect of years on the interpretation of genotype x crop effects was samll.     

Performance of Sugarcane (Saccharum officinarum L.) Under Surface Drip, Sub Surface Drip (Biwall) and Furrow Methods of Irrigation

Field experiments were conducted at the Sugarcane Breeding Institute, Coimbatore, India during 1989–93 to study the productivity and water use efficiency of sugarcane under different methods of irrigation. The results showed that there could be a 44 % saving in water with higher water use efficiency in drip irrigation compared to conventional furrow irrigation. Among drip irrigation systems in the plant crop, sub surface drip (Biwall) at 40/140 cm spacing recorded a significantly higher number of millable canes, cane length and single cane weight compared to either conventional furrow irrigation or furrow irrigation based on IW/CPE (Irrigation Water Cumulative Pan Evaporation) ratio. In ratoon crop, Biwall irrigation at 60/120 cm gave significantly higher cane length and single cane weight compared to any other methods of irrigation. However, cane and sugar yields in Biwall irrigations were on par with conventional furrow irrigation but superior to either surface drip or furrow irrigation based in IW/CPE ratio.     

Analysis of genomic and functional RFLP derived markers associated with sucrose content,fiber and yield QTLs in a sugarcane (<Emphasis Type="Italic">Saccharum</Emphasis> spp.) commercial cross

Expressed sequence tags derived markers have a great potential to be used in functional map construction and QTL tagging. In the present work, sugarcane genomic probes and expressed sequence tags having homology to genes, mostly involved in carbohydrate metabolism were used in RFLP assays to identify putative QTLs as well as their epistatic interactions for fiber content, cane yield, pol and tones of sugar per hectare, at two crop cycles in a progeny derived from a bi-parental cross of sugarcane elite materials. A hundred and twenty marker trait associations were found, of which 26 at both crop cycle and 32 only at first ratoon cane. A sucrose synthase derived marker was associated with a putative QTL having a high negative effect on cane yield and also with a QTL having a positive effect on Pol at both crop cycles. Fifty digenic epistatic marker interactions were identified for the four traits evaluated. Of these, only two were observed at both crop cycles.     

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.     

不同甘蔗品种（系）的产量构成因素及品质比较

以新台糖22号为对照（CK）,对参试的9个甘蔗品种（系）进行田间一年新植和一年宿根的品比试验,调查参试品种（系）的农艺性状、抗逆性状及产量构成性状,对其进行综合评价。结果表明,9个参试品种（系）比CK增产增糖的品种（系）有6个,其中桂热2号和凉蔗02-186的分蘖率、宿根发株率、蔗茎产量、含糖量和有效茎数等较CK有明显的优势,福农41号的枯心苗率和梢腐病率最高,凉蔗07-53、凉蔗03-23和凉蔗03-81蔗糖分偏低,其他材料与CK差异不大。通过产量和总含糖量综合分析,桂热2号、凉蔗02-186、桂糖42号表现优异,适宜在广西南宁地区及气候相似蔗区大面积推广应用。     

Sugarcane Breeding Institute,Coimbatore, India Effect of Different Levels of Drought during the Formative Phase on Growth Parameters and its Relationship with Dry Matter Accumulation in Sugarcane

A field experiment was conducted at Coimbatore (11° N, 77° E), India during the 1996 and 1997 crop seasons, using four commercial sugarcane varieties (Co 8021, Co 419, Co 8208 and Co 6304), to study the effect of three levels of drought (severe, moderate and control) during the formative phase (60–150 days after planting) on growth determinants and their relationship with dry matter accumulation. The reduction in dry matter content was 60.8, 52.4 and 25.9 % in severe drought and 46.3, 36.3 and 15.1 % in moderate drought at the ends of the formative, grand growth and maturity phases, respectively. High net assimilation rate, optimum leaf area index, high crop growth rate and an early shift in dry matter allocation to the stem were found to be desirable for higher biomass production, especially under water‐limited drought conditions. Measurement of growth parameters such as net assimilation rate, relative growth rate, leaf area index and leaf area duration under drought and crop growth rate and stalk elongation rate under normal irrigated conditions, particularly during the formative phase, might help to predict total dry matter at harvest. Leaf area ratio was not found to correlate with total dry matter at harvest in either drought or normal irrigated conditions.     

Identification of molecular markers associated with sugar-related traits in a <Emphasis Type="Italic">Saccharum</Emphasis> interspecific cross

The cultivated sugarcane (Saccharum spp. hybrids, 2n = 100–130) is one crop for which interspecific hybridization involving wild germplasm has provided a major breakthrough in its improvement. Few clones were used in the initial hybridization event leading to a narrow genetic base for continued cultivar development. Molecular breeding would facilitate the identification and introgression of novel alleles/genes from the wild germplasm into cultivated sugarcane. We report the identification of molecular markers associated with sugar-related traits using an F₁ population derived from a cross between S. officinarum ‘Louisiana Striped’ × S. spontaneum ‘SES 147B’, the two major progenitor species of cultivated sugarcane. Genetic linkage maps of the S. officinarum and S. spontaneum parents were produced using the AFLP, SRAP and TRAP molecular marker techniques. The mapping population was evaluated for sugar-related traits namely, Brix (B) and pol (P) at the early (E) and late (L) plant growing season in the plant cane (04) and first ratoon (05) crops (04EB, 04LB, 04LP, 05EB and 05EP). For S. officinarum, combined across all the traits, a total of 30 putative QTLs was observed with LOD scores ranging from 2.51 to 7.48. The phenotypic variation (adj. R²) explained by all QTLs per trait ranged from 22.1% (04LP) to 48.4% (04EB). For S. spontaneum, a total of 11 putative QTLs was observed with LOD scores ranging from 2.62 to 4.70 and adj. R² ranging from 9.3% (04LP) to 43.0% (04LB). Nine digenic interactions (iQTL) were observed in S. officinarum whereas only three were observed in S. spontaneum. About half of the QTLs contributed by both progenitor species were associated with effects on the trait that was contrary to expectations based on the phenotype of the parent contributing the allele. Quantitative trait loci and their associated effects were consistent across crop-years and growing seasons with very few QTLs being unique to the early season. When the data were reanalyzed using the non-parametric discriminant analysis (DA) approach, significant marker-trait associations were detected for markers that were either identical to or in the vicinity of markers previously identified using the traditional QTL approach. Discriminant analysis also pointed to previously unidentified markers some of which remained unlinked on the map. These preliminary results suggest that DA could be used as a complementary approach to traditional QTL analysis in a crop like sugarcane for which saturated linkage maps are unavailable or difficult to obtain.