Exploitation of heterosis through recurrent selection scheme applied in segregating generations of a tomato breeding program

This paper presents the efficiency of recurrent selection in the segregating generations of recycled lines, obtained via mass selection, in two tomato commercial single-cross hybrids, and the assessment of advanced lines in two farming systems at two different locations. In particular, in the F₃ and F₄ mass selection lines of the hybrids Iron and Sahara, half-sib (HS) selection was applied by crossing within the F₃ and F₄ plants. Two experiments were conducted, the first for evaluating the F₄ mass lines with the HS lines obtained by crossing in the F₃ generation, and the second for evaluating the F₅ mass lines with the HS lines obtained by crossing in the F₄ generation, and the second generation HS lines, which were selected from the first experiment. F₁ and F₄ generations were used as controls, respectively. The HS lines of cv. Sahara overyielded 18–56% the F₄ mass line, while Iron's HS lines presented greater uniformity in yield components and also outperformed qualitatively. The effectiveness of mass selection showed positive realized heritability only for fruit number of cv. Iron. In this study, where evaluation and selection was practiced in the absence of competition, the expected response in heterosis via HS depended on σ²_g. The differences of σ²_g of F₁ from mass and HS lines were positive for both hybrids, while when the control was the F₄ generation, mass lines showed a lower performance and some HS lines showed a higher performance. This means that HS lines have favorable alleles and heterosis. In this sense, Sahara's and Iron's HS lines increased 50.2 and 5.3% the charge of favorable alleles, respectively, compared to the corresponding control. The selected advanced lines were assessed in two farming systems at two different locations; the organic one, where two HS-lines, one from each hybrid, outyielded significantly the control; and the conventional one, where all lines performed equally to the control. The results assume the evidence that stable hybrids incorporate individual buffering into inbred line cultivars.     

Influence of no-tillage and organic mulching on tomato (Solanum Lycopersicum L.) production and nitrogen use in the mediterranean environment of central Italy

In conservation tillage systems based on legume mulches it is important to optimize N management strategies. The present study evaluated the effect of some winter legume cover crops converted into mulches on the following no-tillage tomato (Solanum Lycopersicum L.) yield, tomato nitrogen uptake, tomato use efficiency (NUE), soil nitrate and the apparent N remaining in the soil (ARNS) in a Mediterranean environment. Field experiments were carried out from 2002 to 2004 in a tomato crop transplanted into: four different types of mulches coming from winter cover crops [hairy vetch (Vicia villosa Roth.), subclover (Trifolium subterranem L.), snail medic (Medicago scutellata L. Miller), and Italian ryegrass (Lolium multiflorum Lam.)]; a conventional tilled soil (CT); and a no-tilled bare soil (NT). All treatments were fertilized with three different levels of nitrogen (N) fertilizer (0, 75, and 150 kg N ha⁻¹). Cover crop above-ground biomass at cover crop suppression ranged from 4.0 to 6.7 t ha⁻¹ of DM and accumulated from 54 to 189 kg N ha⁻¹, hairy vetch showed the highest values followed by subclover, snail medic and ryegrass. The marketable tomato yield was higher in no-tilled legume mulched soil compared to no-tilled ryegrass mulched soil, CT, and NT (on average 84.8 vs 68.7 t ha⁻¹ of FM, respectively) and it tended to rise with the increase of the N fertilization level. A similar trend was observed on tomato N uptake. Hairy vetch mulch released the highest amount of N during tomato cultivation followed by subclover, snail medic, and ryegrass (on average 141, 96, 90 and 33 kg N ha⁻¹). The tomato NUE tended to decrease with the increase of the N fertilization rates, it ranged from 39 to 60% in no-tilled legume mulched soil and from −59 to 30% in no-tilled ryegrass mulched soil when compared to the CT. The soil NO₃-N content and the ARNS was always higher in the soil mulched with legumes compared to the soil mulched with ryegrass and in NT and CT. This study shows that direct transplanting into mulches coming from winter legume cover crops could be useful for improving the yield and the N-uptake in a no-tillage tomato crop. Furthermore, considering the high N content in the upper soil layer and the remaining N content in the organic mulch residues after tomato harvesting, there is a large amount of N potentially available which could be immediately used by an autumn–winter cash crop.     

松杉树皮和玉米秸秆堆肥对番茄根结线虫病的防治及土壤微生物的影响

日光温室栽培条件下,通过盆栽试验研究了松杉树皮、玉米秸秆堆肥对番茄的生长、产量、根结线虫发病情况及土壤微生物的影响。结果表明,松杉树皮、玉米秸秆堆肥对番茄根结线虫病具有一定的防治效果,以松杉树皮、玉米秸秆堆肥混施效果最好,同时各种堆肥的施用均增加了番茄的生物量及土壤微生物数量。通过相关性分析得知,根结线虫与土壤微生物数量存在显著负相关,说明土壤微生物群落的多样性对根结线虫病的发生产生了抑制作用。     

氯化苦与1,3-二氯丙烯胶囊施用后在黄瓜及番茄果实中的残留检测

采用配有顶空进样器的高效气相色谱仪及测定氯化苦与1,3-二氯丙烯胶囊施用后在黄瓜与番茄果实中的残留量。结果表明:所有样本均未检出氯化苦或1,3-二氯丙烯,说明使用氯化苦与1,3-二氯丙烯胶囊进行土壤熏蒸后对食品安全。     

根层调控对设施番茄生长及氮素利用的影响

以寿光设施番茄生产体系为对象,研究了根层水肥调控处理(W2FS)和增加促根管理的根层综合调控处理(W2FR)对番茄产量、根系生长、氮素利用和土壤无机氮含量的影响。结果表明:根层水肥调控(W2FS)和根层综合调控处理(W2FR)与农民传统施肥方式相比明显节水节肥,灌溉量减少29%,养分投入量N-P2O5-K2O分别降低59%、23%、42%和79%、78%、48%;根层综合调控处理(W2FR)有助于促进番茄苗期根系生长,分别比传统施肥(W1FC)、对照(W2F0)和根层水肥调控技术(W2FS)的总根长提高57%、42%、46%,根表面积增加62%、34%、36%,根体积增加70%、29%、29%;根层综合调控处理(W2FR)提高了氮磷钾的养分偏生产力(PFP),比传统施肥方式分别提高了4.0、3.7、1.0倍,提高了肥料利用效率,降低了氮素淋洗风险。     

南通地区番茄品种比较试验

对7个番茄品种进行了生育期、商品性、抗逆性和产量方面的比较试验。试验结果表明,浙粉202、苏粉9号、金棚1号等3个品种比对照品种苏粉8号产量高,且抗性与早熟性均较好,适宜在南通地区推广种植。     

设施栽培无限生长型番茄品种比较试验

对4个番茄品种在江苏淮安设施栽培过程中的物候期、植物学性状、产量和抗逆性等进行比较,结果表明,红粉佳人和赛尔斯特-416两个品种综合表现最佳。红粉佳人产量最高,每667m^2产量可达5610kg,风味佳、耐贮存性好、抗灰霉病能力较强;赛尔斯特-416产量较高,坚韧耐贮运、裂果少;均适合在江苏地区推广种植。     

控释肥料对中蔬4号番茄产量和品质的影响

以中蔬4号番茄为材料,研究了不同用量控释肥料对其生长发育、产量和品质的影响。试验结果表明,减氮30%的控释肥处理（T6）和减量20%的控释肥处理（T4）对番茄生长发育的促进作用最明显,该用量下,番茄株高、茎粗、茎叶鲜质量、根鲜质量和果实鲜质量等显著增大,可溶性糖、可滴定酸、维生素、番茄红素含量显著增加,番茄的产量和经济效益显著提高。     

遮光及恢复过程中番茄叶片抗氧化酶活性变化研究

以具有典型植株形态的番茄幼苗为材料,进行遮光处理(遮光后光强为25%自然光),测量遮光后及恢复自然光照过程中番茄体内MDA含量和SOD、POD、CAT活性.结果表明,短期遮光后两品系MDA含量都明显增加,叶片上冲型品系增加幅度低于叶片平展型品系,说明恢复过程中叶片上冲型品系具有更强的恢复能力.短期遮光后两品系SOD、CAT活性明显降低,POD 活性略有升高;恢复过程中SOD活性前期迅速升高,POD和CAT活性先降后升.