Investigation of the hereditary character, woolly, in the tomato /
Investigation of the hereditary character, woolly, in the tomato /
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发表时间：
1959-09
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通讯作者：
Paul R. Shilling
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作者：
Paul R. Shilling
在栽培番茄的某些品系中存在着非常丰富的表皮毛生长的条件。这个角色起源于新泽西卡姆登的坎贝尔汤公司和W。S. Porte（个人交流）从新泽西农业实验站获得了一种具有这种特征的番茄种子样本。他称这个角色为“安哥拉。后来，扬和麦克亚瑟（1947）从波特那里得到了这个人物的选集，发表了一份关于这个人物的描述，把它称为“羊毛叶”和“羊毛”。从那时起，这个角色通常被称为“毛茸茸的”，而不是“毛茸茸的叶子”。“有毛植物很容易与无毛植物区分开来。由于大量的表皮毛生长，羊毛状植物呈现灰色而不是正常的绿色。在使具绵毛植物自交时，产生%具绵毛植物与y%无绵毛植物的比率。然而，当单个基因对杂合的植物自交时，将预期A 'A'-A或%：A表型比率。因此，这观察到%'。}/ 3的比率表明纯合时绵状性状是致死的，并且任何表现绵状性状的植物都是杂合的。羊毛状特征是栽培植物中已知的极少数半显性致死因子之一，其致死作用的性质尚未在任何一种植物中进行过研究。由于杂合子存活，羊毛基因不是配子致死基因。如果有毛基因仅对卵或仅对精子是致死的，则在使有毛植物自交时，预期有毛植物与无毛植物的比率为1/2：3/2，而不是观察到的%：1/3。因此，羊毛基因在两种配子中都不是致命的。由于这个原因，必须假定纯合的有毛条件的致死作用发生在受精后的某个时候。如果这种致死作用发生在胚胎发育期间，那么在检查自花授粉的有绵毛植物果实中的合子或胚胎时，人们可能能够观察到比非有绵毛植物果实中多约25%的合子或胚胎解体。这将是所有受精卵和胚胎的25%，其中包括那些正常的和那些正在解体的。如果纯合的具绵毛条件的致死作用影响胚或胚乳发育，从而也影响种皮发育，那么在自花授粉的具绵毛植物的果实中，每个果实中正常大小的种子比来自非具绵毛植物的类似果实中的正常大小的种子少大约25%;但是在来自两种类型果实的正常大小的种子中应该发现几乎相同的发芽率。相反，如果致死作用由于其对胚或胚乳发育的影响而对种皮发育没有明显影响，那么人们可以预期，在有绵毛和无绵毛的果实中，每个果实中正常大小的种子的数量几乎相同，但从有绵毛植物的果实中正常大小的种子的发芽率大约低25%。根据Soost（个人通讯），在潮湿滤纸上发芽的种子中，未发芽的数量与预期的数量一致。
A condition of very profuse epidermal hair growth exists in some strains of the cultivated tomato, Lycopersicon esculentum Mill. The character originated in a field of tomatoes grown by the Campbell Soup Company of Camden, New Jersey and W. S. Porte (personal communication) obtained a seed sample of a tomato having this character from the New Jersey Agricultural Experiment Station. He called the character "Angora." Later, Young and Mac Arthur (1947), having obtained the selection from Porte, published a description of the character referring to it as both "woolly leaves" and "woolly." Since that time, the character has generally been referred to as "woolly," not as "woolly leaves." Woolly plants are easily distinguished from nonwoolly plants. Due to the profuse epidermal hair growth, woolly plants appear grayish instead of a normal green color. Upon selfing woolly plants, a ratio of % woolly to y% nonwoolly plants results. However, when a plant heterozygous for a single gene pair is selfed, either a A'A'-A or a %:A phenotypic ratio would be expected. Therefore, this observed %'.}/3 ratio indicates that the woolly character is lethal when homozygous, and any plant manifesting the woolly character is heterozygous. The woolly character is one of the very few semidominant lethal factors known in cultivated plants, and the nature of the lethal action has not been investigated in any of them. Since the heterozygotes survive, the woolly gene is not a gametic lethal. If the woolly gene were lethal only to eggs or only to sperms, a ratio of /2 woolly plants to 3̂2 nonwoolly plants would be expected upon selfing a woolly plant, instead of the observed %:}/3 ratio. Therefore, the woolly gene is not lethal in either type of gamete. For this reason, it must be assumed that the lethal action of the homozygous woolly condition takes place sometime after fertilization. If this lethal action occurs during embryonic development, then upon examination of zygotes or embryos in fruits from self-pollinated woolly plants one might be able to observe disintegration of approximately 25 percent more zygotes or embryos than in fruits from nonwoolly plants. This would be 25 percent of all zygotes and embryos, which includes those which are normal and those which are disintegrating. If the lethal action of the homozygous woolly condition affected embryo or endosperm development and, as a consequence also affected seed coat development, then in fruits from self-pollinated woolly plants, one would expect approximately 25 percent fewer normal sized seeds per fruit than in similar fruits from nonwoolly plants; but nearly the same percent germination should be found in the normal sized seeds from both types of fruits. Conversely, if the lethal action did not appreciably affect seed coat development as a consequence of its effect on embryo or endosperm development, then one would expect nearly the same number of normal sized seeds per fruit in both woolly and nonwoolly fruits but approximately 25 percent less germination of the normal sized seeds from fruits of woolly plants. According to Soost (personal communication), in seeds germinated on moist filter paper the number not germinating corresponded to the number of expected