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Plant Biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
Plant breeding is defined as identifying and selecting desirable traits in plants and combining these into one individual plant. Since 1900, Mendel’s laws of genetics have provided the scientific basis for plant breeding. As all traits of a plant are controlled by genes located on chromosomes, conventional plant breeding can be considered as the manipulation of the combination of chromosomes. In general, there are three main procedures to manipulate plant chromosome combinations. First, plants of a given population, which show desired traits, can be selected and used for further breeding and cultivation, a process called pure-line selection (Figure 6.2). Second, desired traits found in different plant lines can be combined altogether to obtain plants that exhibit all the traits simultaneously, a method termed hybridization (Figure 6.2). Heterosis, a phenomenon of increased vigor, is obtained by hybridization of inbred lines. Third, polyploidy (increased number of chromosome sets) can contribute to crop improvement (Figure 6.2). Plant breeding may be classified as classical breeding or modern breeding.
Agricultural biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
Plant breeding is defined as identifying and selecting desirable traits in plants and combining these into one individual plant. Since 1900, Mendel’s laws of genetics have provided the scientific basis for plant breeding. As all traits of a plant are controlled by genes located on chromosomes, conventional plant breeding can be considered as the manipulation of the combination of chromosomes. In general, there are three main procedures to manipulate plant chromosome combination. First, plants of a given population, which show desired traits can be selected and used for further breeding and cultivation, a process called (pure line) selection (Figure 6.2). Second, desired traits found in different plant lines can be combined altogether to obtain plants that exhibit all the traits simultaneously, a method termed hybridization (Figure 6.2). Heterosis, a phenomenon of increased vigor, is obtained by hybridization of inbred lines. Third, polyploidy (increased number of chromosome sets) can contribute to crop improvement (Figure 6.2). Plant breeding may be classified as classical breeding or modern breeding.
Assessment of natural variability in leaf morphological and physiological traits in maize inbreds and their related hybrids during early vegetative growth
Published in Egyptian Journal of Basic and Applied Sciences, 2019
Farag Ibraheem, Eman M. El-Ghareeb
Maize growth, development, and productivity are shaped by genetic constitution of maize genotypes and their consequences on gene expression. In addition, critical environmental conditions such as soil fertility and climatic changes-related parameters such as alterations in temperature, CO2 emission, rainfalls, and drought stress can significantly affect maize growth and productivity [14]. Previous studies revealed significant differences in many growth- and physiology-related traits among parental maize inbreds and their hybrids. Hybrids usually exhibit better plant growth vigor, physiological adaptation and overall field performance than their parental inbreds and such improved performance of hybrids is attributed to heterosis (hybrid vigor) [15,16]. The impact of heterosis on plant growth and productivity can be equivalent to that of adequate fertilization [17]. The extent of heterosis is greatly influenced by the genetic diversity between their parental inbreds where greater genetic difference induces stronger heterosis [3,18,19]. In maize, heterosis is usually discussed in terms of grain yield. However, other phenotypic traits such as root growth and development, plant height, leaf features, leaf/stem biomass, flowering time and ear height can also exhibit heterosis [20–23].