General Agriculture & Social Sciences

Analysis of animal breeding systems:

• Criss crossing (rotational crossbreeding) involves mating hybrid females alternately with purebred sires of two or more parental breeds in successive generations to maintain heterosis.
• Back crossing refers to crossing an F1 hybrid back to one of its parental pure breeds.
• Test crossing is the cross of an individual with a homozygous recessive individual to determine its genotype.
• Out crossing is mating of unrelated purebred animals within the same breed.

Analysis of plant diseases:

• Rice suffers from diseases like blast (Magnaporthe oryzae) and bacterial blight (Xanthomonas oryzae).
• Maize suffers from downy mildews, leaf blight (Exserohilum turcicum), and common rust.
• Wheat suffers from rusts (Puccinia spp.), loose smut, and Karnal bunt.
• Sugarcane is devastated by Red Rot caused by the fungus Colletotrichum falcatum, characterized by red lesions with distinct white cross-patches inside the stalk.

Development of Sharbati Sonora wheat:

• Wild wheat crosses were used in introgression for disease resistance, not for Sharbati Sonora.
• Hybridization between wild varieties produces amphidiploids or synthetic wheats.
• X-rays were utilized in early mutation experiments by Stadler and Muller.
• Sharbati Sonora is a famous amber-grained mutant variety developed by Dr. M. S. Swaminathan through gamma-ray irradiation of the red-grained Mexican dwarf wheat variety Sonora 64.