新英格兰和加利福尼亚州的路德·伯班克（园艺家）是一个改变了美国耕作方法的人。他根据达尔文关于植物生长变化方式的发现所作的实验为我们提供许多种新的水果、蔬菜和花卉。
一天，他在自己的一只马铃薯上发现一颗不同寻常的胚珠。当他收获由这颗胚珠长出的马铃薯时，他发现其中的两株生长着他从未看到过的又大又白的马铃薯。他所做的所有杂交植物试验生产的马铃薯，都不比亲本生出的马铃薯大得多或好得多。但这两株上的马铃薯却大得惊人。他精心地栽培它们，直到后来他培养出的那种伯班克马铃薯十分健壮，能抗病害，因而在其他品种的马铃薯无法生长的地方，这一品种极为珍贵。
伯班克自己卖这些新的马铃薯幼苗只挣了大约150美元。但是他敢肯定凭着他所知道的和他所发现的，他可以对自然加以改进。
a man who changed american farming was luther burbank（horticulturist） of new england and california. his experi-ments，based on the discoveries of darwin about the way plantsgrow and change，gave us many new kinds of fruits，vegetables，and flowers.
one day he discovered an unusual seedball on one of hispotatoes. when harvesting potatoes from this seed， he found thattwo of the plants had larger and whiter potatoes than any he hadseen before.in all of his attempts to mix plants，the potatoes thatresulted had never been much larger and better than those of theparents.but the potatoes from these plants were wonderfullylarge.he cultivated them carefully until he had developed theburbank potato， strong enough to resist disease and thereforevaluable in places where other kinds of potatoes could not begrown.
burbank himself made only about＄150 from the sale of thesenew potato plants.but he was sure that，with what he knew andwhat he had discovered，he could improve on nature.